{"id":203,"date":"2023-03-30T17:18:24","date_gmt":"2023-03-30T09:18:24","guid":{"rendered":"http:\/\/idc.birk.cn\/?p=203"},"modified":"2023-03-30T17:18:24","modified_gmt":"2023-03-30T09:18:24","slug":"%e4%b8%89%e6%ac%a1%e6%8f%a1%e6%89%8b%e3%80%81%e5%9b%9b%e6%ac%a1%e6%8c%a5%e6%89%8b%e3%80%81%e9%87%8d%e4%bc%a0%e6%9c%ba%e5%88%b6%e3%80%81%e6%bb%91%e5%8a%a8%e7%aa%97%e5%8f%a3%e3%80%81%e6%b5%81%e9%87%8f","status":"publish","type":"post","link":"https:\/\/idc.birk.cn\/?p=203","title":{"rendered":"\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b\u3001\u91cd\u4f20\u673a\u5236\u3001\u6ed1\u52a8\u7a97\u53e3\u3001\u6d41\u91cf\u63a7\u5236\u3001\u62e5\u585e\u63a7\u5236\u3001TCP\/UDP\u5168\u89e3\u6790"},"content":{"rendered":"<header class=\"single-title\"><\/header>\n<div id=\"homedia\"><a class=\"reference-link\" style=\"font-size: 16px;font-weight: bold\" name=\"\u6587\u7ae0\u76ee\u5f55\"><\/a><span style=\"font-size: 16px;font-weight: bold\">\u6587\u7ae0\u76ee\u5f55<\/span><\/div>\n<div class=\"single-entry\">\n<div id=\"test-editormd-view\" class=\"markdown-body editormd-html-preview\">\n<ul>\n<li>UDP \u548c TCP \u7684\u7279\u70b9<\/li>\n<li>UDP \u9996\u90e8\u683c\u5f0f<\/li>\n<li>TCP \u9996\u90e8\u683c\u5f0f<\/li>\n<li>TCP \u7684\u4e09\u6b21\u63e1\u624b<\/li>\n<li>TCP \u7684\u56db\u6b21\u6325\u624b<\/li>\n<li>TCP \u91cd\u4f20\u673a\u5236<\/li>\n<li>\n<ul>\n<li>\u8d85\u65f6\u91cd\u4f20<\/li>\n<li>\u5feb\u901f\u91cd\u4f20<\/li>\n<li>SACK\u65b9\u6cd5<\/li>\n<li>Duplicate SACK<\/li>\n<li>\n<ul>\n<li>*\u6817\u5b50\u4e00\u53f7\uff1aACK \u4e22\u5305*<\/li>\n<li>*\u6817\u5b50\u4e8c\u53f7\uff1a\u7f51\u7edc\u5ef6\u65f6*<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>TCP \u6ed1\u52a8\u7a97\u53e3<\/li>\n<li>TCP \u6d41\u91cf\u63a7\u5236<\/li>\n<li>\n<ul>\n<li>\u64cd\u4f5c\u7cfb\u7edf\u7f13\u51b2\u533a\u4e0e\u6ed1\u52a8\u7a97\u53e3\u7684\u5173\u7cfb<\/li>\n<li>\n<ul>\n<li>\n<ul>\n<li>\u7a97\u53e3\u5173\u95ed<\/li>\n<li>\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>TCP \u62e5\u585e\u63a7\u5236<\/li>\n<li>\n<ul>\n<li>\u6162\u542f\u52a8<\/li>\n<li>\u62e5\u585e\u907f\u514d\u7b97\u6cd5<\/li>\n<li>\u62e5\u585e\u53d1\u751f<\/li>\n<li>\n<ul>\n<li>\u53d1\u751f\u8d85\u65f6\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f[\u7b97\u6cd5]()<\/li>\n<li>\u53d1\u751f\u5feb\u901f\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f[\u7b97\u6cd5]()<\/li>\n<\/ul>\n<\/li>\n<li>\u5feb\u901f\u6062\u590d<\/li>\n<\/ul>\n<\/li>\n<li>\u53c2\u8003\u94fe\u63a5<\/li>\n<li>\u516c\u4f17\u53f7<\/li>\n<\/ul>\n<p>\u7f51\u7edc\u5c42\u53ea\u628a\u5206\u7ec4\u53d1\u9001\u5230\u76ee\u7684\u4e3b\u673a\uff0c\u4f46\u662f\u771f\u6b63\u901a\u4fe1\u7684\u5e76\u4e0d\u662f\u4e3b\u673a\u800c\u662f\u4e3b\u673a\u4e2d\u7684\u8fdb\u7a0b\u3002\u4f20\u8f93\u5c42\u63d0\u4f9b\u4e86\u8fdb\u7a0b\u95f4\u7684\u903b\u8f91\u901a\u4fe1\uff0c\u4f20\u8f93\u5c42\u5411\u9ad8\u5c42\u7528\u6237\u5c4f\u853d\u4e86\u4e0b\u9762\u7f51\u7edc\u5c42\u7684\u6838\u5fc3\u7ec6\u8282\uff0c\u4f7f\u5e94\u7528\u7a0b\u5e8f\u770b\u8d77\u6765\u50cf\u662f\u5728\u4e24\u4e2a\u4f20\u8f93\u5c42\u5b9e\u4f53\u4e4b\u95f4\u6709\u4e00\u6761\u7aef\u5230\u7aef\u7684\u903b\u8f91\u901a\u4fe1\u4fe1\u9053\u3002<\/p>\n<h1 id=\"h1-udp-tcp-\"><a class=\"reference-link\" name=\"UDP \u548c TCP \u7684\u7279\u70b9\"><\/a>UDP \u548c TCP \u7684\u7279\u70b9<\/h1>\n<ul>\n<li>\u7528\u6237\u6570\u636e\u62a5\u534f\u8bae UDP\uff08User Datagram Protocol\uff09\u662f\u65e0\u8fde\u63a5\u7684\uff0c\u5c3d\u6700\u5927\u53ef\u80fd\u4ea4\u4ed8\uff0c\u6ca1\u6709\u62e5\u585e\u63a7\u5236\uff0c\u9762\u5411\u62a5\u6587\uff08\u5bf9\u4e8e\u5e94\u7528\u7a0b\u5e8f\u4f20\u4e0b\u6765\u7684\u62a5\u6587\u4e0d\u5408\u5e76\u4e5f\u4e0d\u62c6\u5206\uff0c\u53ea\u662f\u6dfb\u52a0 UDP \u9996\u90e8\uff09\uff0c\u652f\u6301\u4e00\u5bf9\u4e00\u3001\u4e00\u5bf9\u591a\u3001\u591a\u5bf9\u4e00\u548c\u591a\u5bf9\u591a\u7684\u4ea4\u4e92\u901a\u4fe1\u3002<\/li>\n<li>\u4f20\u8f93\u63a7\u5236\u534f\u8bae TCP\uff08Transmission Control Protocol\uff09\u662f\u9762\u5411\u8fde\u63a5\u7684\uff0c\u63d0\u4f9b\u53ef\u9760\u4ea4\u4ed8\uff0c\u6709\u6d41\u91cf\u63a7\u5236\uff0c\u62e5\u585e\u63a7\u5236\uff0c\u63d0\u4f9b\u5168\u53cc\u5de5\u901a\u4fe1\uff0c\u9762\u5411\u5b57\u8282\u6d41\uff08\u628a\u5e94\u7528\u5c42\u4f20\u4e0b\u6765\u7684\u62a5\u6587\u770b\u6210\u5b57\u8282\u6d41\uff0c\u628a\u5b57\u8282\u6d41\u7ec4\u7ec7\u6210\u5927\u5c0f\u4e0d\u7b49\u7684\u6570\u636e\u5757\uff09\uff0c\u6bcf\u4e00\u6761 TCP \u8fde\u63a5\u53ea\u80fd\u662f\u70b9\u5bf9\u70b9\u7684\uff08\u4e00\u5bf9\u4e00\uff09\u3002<\/li>\n<\/ul>\n<h1 id=\"h1-udp-\"><a class=\"reference-link\" name=\"UDP \u9996\u90e8\u683c\u5f0f\"><\/a>UDP \u9996\u90e8\u683c\u5f0f<\/h1>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/3aa9e4eca033fae92c3d2a1e13974c54.png\" alt=\"20201013140156.png\" \/><\/p>\n<p>\u9996\u90e8\u5b57\u6bb5\u53ea\u6709 8 \u4e2a\u5b57\u8282\uff0c\u5305\u62ec\u6e90\u7aef\u53e3\u3001\u76ee\u7684\u7aef\u53e3\u3001\u957f\u5ea6\u3001\u68c0\u9a8c\u548c\u300212 \u5b57\u8282\u7684\u4f2a\u9996\u90e8\u662f\u4e3a\u4e86\u8ba1\u7b97\u68c0\u9a8c\u548c\u4e34\u65f6\u6dfb\u52a0\u7684\u3002<\/p>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u9996\u90e8\u683c\u5f0f\"><\/a>TCP \u9996\u90e8\u683c\u5f0f<\/h1>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/45a2edc121fcbf9cf6b3735ff0184ca7.png\" alt=\"55dc4e84-573d-4c13-a765-52ed1dd251f9.png\" \/><\/p>\n<ul>\n<li><strong>\u5e8f\u53f7<\/strong>\u00a0\uff1a\u7528\u4e8e\u5bf9\u5b57\u8282\u6d41\u8fdb\u884c\u7f16\u53f7\uff0c\u4f8b\u5982\u5e8f\u53f7\u4e3a 301\uff0c\u8868\u793a\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7\u4e3a 301\uff0c\u5982\u679c\u643a\u5e26\u7684\u6570\u636e\u957f\u5ea6\u4e3a 100 \u5b57\u8282\uff0c\u90a3\u4e48\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\u7684\u5e8f\u53f7\u5e94\u4e3a 401\u3002<\/li>\n<li><strong>\u786e\u8ba4\u53f7<\/strong>\u00a0\uff1a\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\u7684\u5e8f\u53f7\u3002\u4f8b\u5982 B \u6b63\u786e\u6536\u5230 A \u53d1\u9001\u6765\u7684\u4e00\u4e2a\u62a5\u6587\u6bb5\uff0c\u5e8f\u53f7\u4e3a 501\uff0c\u643a\u5e26\u7684\u6570\u636e\u957f\u5ea6\u4e3a 200 \u5b57\u8282\uff0c\u56e0\u6b64 B \u671f\u671b\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\u7684\u5e8f\u53f7\u4e3a 701\uff0cB \u53d1\u9001\u7ed9 A \u7684\u786e\u8ba4\u62a5\u6587\u6bb5\u4e2d\u786e\u8ba4\u53f7\u5c31\u4e3a 701\u3002<\/li>\n<li><strong>\u6570\u636e\u504f\u79fb<\/strong>\u00a0\uff1a\u6307\u7684\u662f\u6570\u636e\u90e8\u5206\u8ddd\u79bb\u62a5\u6587\u6bb5\u8d77\u59cb\u5904\u7684\u504f\u79fb\u91cf\uff0c\u5b9e\u9645\u4e0a\u6307\u7684\u662f\u9996\u90e8\u7684\u957f\u5ea6\u3002<\/li>\n<li><strong>\u786e\u8ba4 ACK<\/strong>\u00a0\uff1a\u5f53 ACK=1 \u65f6\u786e\u8ba4\u53f7\u5b57\u6bb5\u6709\u6548\uff0c\u5426\u5219\u65e0\u6548\u3002TCP \u89c4\u5b9a\uff0c\u5728\u8fde\u63a5\u5efa\u7acb\u540e\u6240\u6709\u4f20\u9001\u7684\u62a5\u6587\u6bb5\u90fd\u5fc5\u987b\u628a ACK \u7f6e 1\u3002<\/li>\n<li><strong>\u540c\u6b65 SYN<\/strong>\u00a0\uff1a\u5728\u8fde\u63a5\u5efa\u7acb\u65f6\u7528\u6765\u540c\u6b65\u5e8f\u53f7\u3002\u5f53 SYN=1\uff0cACK=0 \u65f6\u8868\u793a\u8fd9\u662f\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u6bb5\u3002\u82e5\u5bf9\u65b9\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u5219\u54cd\u5e94\u62a5\u6587\u4e2d SYN=1\uff0cACK=1\u3002<\/li>\n<li><strong>\u7ec8\u6b62 FIN<\/strong>\u00a0\uff1a\u7528\u6765\u91ca\u653e\u4e00\u4e2a\u8fde\u63a5\uff0c\u5f53 FIN=1 \u65f6\uff0c\u8868\u793a\u6b64\u62a5\u6587\u6bb5\u7684\u53d1\u9001\u65b9\u7684\u6570\u636e\u5df2\u53d1\u9001\u5b8c\u6bd5\uff0c\u5e76\u8981\u6c42\u91ca\u653e\u8fde\u63a5\u3002<\/li>\n<li><strong>\u7a97\u53e3<\/strong>\u00a0\uff1a\u7a97\u53e3\u503c\u4f5c\u4e3a\u63a5\u6536\u65b9\u8ba9\u53d1\u9001\u65b9\u8bbe\u7f6e\u5176\u53d1\u9001\u7a97\u53e3\u7684\u4f9d\u636e\u3002\u4e4b\u6240\u4ee5\u8981\u6709\u8fd9\u4e2a\u9650\u5236\uff0c\u662f\u56e0\u4e3a\u63a5\u6536\u65b9\u7684\u6570\u636e\u7f13\u5b58\u7a7a\u95f4\u662f\u6709\u9650\u7684\u3002<\/li>\n<\/ul>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u7684\u4e09\u6b21\u63e1\u624b\"><\/a>TCP \u7684\u4e09\u6b21\u63e1\u624b<\/h1>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/8a0f3a448651e68d3bc1ac8339b6c77a.png\" alt=\"e92d0ebc-7d46-413b-aec1-34a39602f787.png\" \/><\/p>\n<p>\u5047\u8bbe A \u4e3a\u5ba2\u6237\u7aef\uff0cB \u4e3a\u670d\u52a1\u5668\u7aef\u3002<\/p>\n<ul>\n<li>\u9996\u5148 B \u5904\u4e8e LISTEN\uff08\u76d1\u542c\uff09\u72b6\u6001\uff0c\u7b49\u5f85\u5ba2\u6237\u7684\u8fde\u63a5\u8bf7\u6c42\u3002<\/li>\n<li>A \u5411 B \u53d1\u9001\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\uff0cSYN=1\uff0cACK=0\uff0c\u9009\u62e9\u4e00\u4e2a\u521d\u59cb\u7684\u5e8f\u53f7 x\u3002<\/li>\n<li>B \u6536\u5230\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\uff0c\u5982\u679c\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u5219\u5411 A \u53d1\u9001\u8fde\u63a5\u786e\u8ba4\u62a5\u6587\uff0cSYN=1\uff0cACK=1\uff0c\u786e\u8ba4\u53f7\u4e3a x+1\uff0c\u540c\u65f6\u4e5f\u9009\u62e9\u4e00\u4e2a\u521d\u59cb\u7684\u5e8f\u53f7 y\u3002<\/li>\n<li>A \u6536\u5230 B \u7684\u8fde\u63a5\u786e\u8ba4\u62a5\u6587\u540e\uff0c\u8fd8\u8981\u5411 B \u53d1\u51fa\u786e\u8ba4\uff0c\u786e\u8ba4\u53f7\u4e3a y+1\uff0c\u5e8f\u53f7\u4e3a x+1\u3002<\/li>\n<li>B \u6536\u5230 A \u7684\u786e\u8ba4\u540e\uff0c\u8fde\u63a5\u5efa\u7acb\u3002<\/li>\n<\/ul>\n<p><strong>\u4e09\u6b21\u63e1\u624b\u7684\u539f\u56e0<\/strong><\/p>\n<p>\u7b2c\u4e09\u6b21\u63e1\u624b\u662f\u4e3a\u4e86\u9632\u6b62\u5931\u6548\u7684\u8fde\u63a5\u8bf7\u6c42\u5230\u8fbe\u670d\u52a1\u5668\uff0c\u8ba9\u670d\u52a1\u5668\u9519\u8bef\u6253\u5f00\u8fde\u63a5\u3002<\/p>\n<p>\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u8fde\u63a5\u8bf7\u6c42\u5982\u679c\u5728\u7f51\u7edc\u4e2d\u6ede\u7559\uff0c\u90a3\u4e48\u5c31\u4f1a\u9694\u5f88\u957f\u4e00\u6bb5\u65f6\u95f4\u624d\u80fd\u6536\u5230\u670d\u52a1\u5668\u7aef\u53d1\u56de\u7684\u8fde\u63a5\u786e\u8ba4\u3002\u5ba2\u6237\u7aef\u7b49\u5f85\u4e00\u4e2a\u8d85\u65f6\u91cd\u4f20\u65f6\u95f4\u4e4b\u540e\uff0c\u5c31\u4f1a\u91cd\u65b0\u8bf7\u6c42\u8fde\u63a5\u3002\u4f46\u662f\u8fd9\u4e2a\u6ede\u7559\u7684\u8fde\u63a5\u8bf7\u6c42\u6700\u540e\u8fd8\u662f\u4f1a\u5230\u8fbe\u670d\u52a1\u5668\uff0c\u5982\u679c\u4e0d\u8fdb\u884c\u4e09\u6b21\u63e1\u624b\uff0c\u90a3\u4e48\u670d\u52a1\u5668\u5c31\u4f1a\u6253\u5f00\u4e24\u4e2a\u8fde\u63a5\u3002\u5982\u679c\u6709\u7b2c\u4e09\u6b21\u63e1\u624b\uff0c\u5ba2\u6237\u7aef\u4f1a\u5ffd\u7565\u670d\u52a1\u5668\u4e4b\u540e\u53d1\u9001\u7684\u5bf9\u6ede\u7559\u8fde\u63a5\u8bf7\u6c42\u7684\u8fde\u63a5\u786e\u8ba4\uff0c\u4e0d\u8fdb\u884c\u7b2c\u4e09\u6b21\u63e1\u624b\uff0c\u56e0\u6b64\u5c31\u4e0d\u4f1a\u518d\u6b21\u6253\u5f00\u8fde\u63a5\u3002<\/p>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u7684\u56db\u6b21\u6325\u624b\"><\/a>TCP \u7684\u56db\u6b21\u6325\u624b<\/h1>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/5c43d2e788903dded40c258f126e5a75.jpeg\" alt=\"f87afe72-c2df-4c12-ac03-9b8d581a8af8.jpg\" \/><\/p>\n<p>\u4ee5\u4e0b\u63cf\u8ff0\u4e0d\u8ba8\u8bba\u5e8f\u53f7\u548c\u786e\u8ba4\u53f7\uff0c\u56e0\u4e3a\u5e8f\u53f7\u548c\u786e\u8ba4\u53f7\u7684\u89c4\u5219\u6bd4\u8f83\u7b80\u5355\u3002\u5e76\u4e14\u4e0d\u8ba8\u8bba ACK\uff0c\u56e0\u4e3a ACK \u5728\u8fde\u63a5\u5efa\u7acb\u4e4b\u540e\u90fd\u4e3a 1\u3002<\/p>\n<ul>\n<li>A \u53d1\u9001\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff0cFIN=1\u3002<\/li>\n<li>B \u6536\u5230\u4e4b\u540e\u53d1\u51fa\u786e\u8ba4\uff0c\u6b64\u65f6 TCP \u5c5e\u4e8e\u534a\u5173\u95ed\u72b6\u6001\uff0cB \u80fd\u5411 A \u53d1\u9001\u6570\u636e\u4f46\u662f A \u4e0d\u80fd\u5411 B \u53d1\u9001\u6570\u636e\u3002<\/li>\n<li>\u5f53 B \u4e0d\u518d\u9700\u8981\u8fde\u63a5\u65f6\uff0c\u53d1\u9001\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff0cFIN=1\u3002<\/li>\n<li>A \u6536\u5230\u540e\u53d1\u51fa\u786e\u8ba4\uff0c\u8fdb\u5165 TIME-WAIT \u72b6\u6001\uff0c\u7b49\u5f85 2 MSL\uff08\u6700\u5927\u62a5\u6587\u5b58\u6d3b\u65f6\u95f4\uff09\u540e\u91ca\u653e\u8fde\u63a5\u3002<\/li>\n<li>B \u6536\u5230 A \u7684\u786e\u8ba4\u540e\u91ca\u653e\u8fde\u63a5\u3002<\/li>\n<\/ul>\n<p><strong>\u56db\u6b21\u6325\u624b\u7684\u539f\u56e0<\/strong><\/p>\n<p>\u5ba2\u6237\u7aef\u53d1\u9001\u4e86 FIN \u8fde\u63a5\u91ca\u653e\u62a5\u6587\u4e4b\u540e\uff0c\u670d\u52a1\u5668\u6536\u5230\u4e86\u8fd9\u4e2a\u62a5\u6587\uff0c\u5c31\u8fdb\u5165\u4e86 CLOSE-WAIT \u72b6\u6001\u3002\u8fd9\u4e2a\u72b6\u6001\u662f\u4e3a\u4e86\u8ba9\u670d\u52a1\u5668\u7aef\u53d1\u9001\u8fd8\u672a\u4f20\u9001\u5b8c\u6bd5\u7684\u6570\u636e\uff0c\u4f20\u9001\u5b8c\u6bd5\u4e4b\u540e\uff0c\u670d\u52a1\u5668\u4f1a\u53d1\u9001 FIN \u8fde\u63a5\u91ca\u653e\u62a5\u6587\u3002<\/p>\n<p><strong>TIME_WAIT<\/strong><\/p>\n<p>\u5ba2\u6237\u7aef\u63a5\u6536\u5230\u670d\u52a1\u5668\u7aef\u7684 FIN \u62a5\u6587\u540e\u8fdb\u5165\u6b64\u72b6\u6001\uff0c\u6b64\u65f6\u5e76\u4e0d\u662f\u76f4\u63a5\u8fdb\u5165 CLOSED \u72b6\u6001\uff0c\u8fd8\u9700\u8981\u7b49\u5f85\u4e00\u4e2a\u65f6\u95f4\u8ba1\u65f6\u5668\u8bbe\u7f6e\u7684\u65f6\u95f4 2MSL\u3002\u8fd9\u4e48\u505a\u6709\u4e24\u4e2a\u7406\u7531\uff1a<\/p>\n<ul>\n<li>\u786e\u4fdd\u6700\u540e\u4e00\u4e2a\u786e\u8ba4\u62a5\u6587\u80fd\u591f\u5230\u8fbe\u3002\u5982\u679c B \u6ca1\u6536\u5230 A \u53d1\u9001\u6765\u7684\u786e\u8ba4\u62a5\u6587\uff0c\u90a3\u4e48\u5c31\u4f1a\u91cd\u65b0\u53d1\u9001\u8fde\u63a5\u91ca\u653e\u8bf7\u6c42\u62a5\u6587\uff0cA \u7b49\u5f85\u4e00\u6bb5\u65f6\u95f4\u5c31\u662f\u4e3a\u4e86\u5904\u7406\u8fd9\u79cd\u60c5\u51b5\u7684\u53d1\u751f\u3002<\/li>\n<li>\u7b49\u5f85\u4e00\u6bb5\u65f6\u95f4\u662f\u4e3a\u4e86\u8ba9\u672c\u8fde\u63a5\u6301\u7eed\u65f6\u95f4\u5185\u6240\u4ea7\u751f\u7684\u6240\u6709\u62a5\u6587\u90fd\u4ece\u7f51\u7edc\u4e2d\u6d88\u5931\uff0c\u4f7f\u5f97\u4e0b\u4e00\u4e2a\u65b0\u7684\u8fde\u63a5\u4e0d\u4f1a\u51fa\u73b0\u65e7\u7684\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u3002<\/li>\n<\/ul>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u91cd\u4f20\u673a\u5236\"><\/a>TCP \u91cd\u4f20\u673a\u5236<\/h1>\n<p>TCP \u5b9e\u73b0\u53ef\u9760\u4f20\u8f93\u7684\u65b9\u5f0f\u4e4b\u4e00\uff0c\u662f\u901a\u8fc7\u5e8f\u5217\u53f7\u4e0e\u786e\u8ba4\u5e94\u7b54\u3002<\/p>\n<p>\u5728 TCP \u4e2d\uff0c\u5f53\u53d1\u9001\u7aef\u7684\u6570\u636e\u5230\u8fbe\u63a5\u6536\u4e3b\u673a\u65f6\uff0c\u63a5\u6536\u7aef\u4e3b\u673a\u4f1a\u8fd4\u56de\u4e00\u4e2a\u786e\u8ba4\u5e94\u7b54\u6d88\u606f\uff0c\u8868\u793a\u5df2\u6536\u5230\u6d88\u606f\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/787bc202dae0e2275178274c0b6557b9.png\" alt=\"ed41d2a36dd90952d1fa9ecd60d2c860.png\" \/><\/p>\n<p>\u4f46\u5728\u9519\u7efc\u590d\u6742\u7684\u7f51\u7edc\uff0c\u5e76\u4e0d\u4e00\u5b9a\u80fd\u5982\u4e0a\u56fe\u90a3\u4e48\u987a\u5229\u80fd\u6b63\u5e38\u7684\u6570\u636e\u4f20\u8f93\uff0c\u4e07\u4e00\u6570\u636e\u5728\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u4e22\u5931\u4e86\u5462\uff1f<\/p>\n<p>\u6240\u4ee5 TCP \u9488\u5bf9\u6570\u636e\u5305\u4e22\u5931\u7684\u60c5\u51b5\uff0c\u4f1a\u7528<strong>\u91cd\u4f20\u673a\u5236<\/strong>\u89e3\u51b3\u3002<\/p>\n<h2 id=\"h2-u8D85u65F6u91CDu4F20\"><a class=\"reference-link\" name=\"\u8d85\u65f6\u91cd\u4f20\"><\/a>\u8d85\u65f6\u91cd\u4f20<\/h2>\n<p>\u91cd\u4f20\u673a\u5236\u7684\u5176\u4e2d\u4e00\u4e2a\u65b9\u5f0f\uff0c\u5c31\u662f\u5728\u53d1\u9001\u6570\u636e\u65f6\uff0c\u8bbe\u5b9a\u4e00\u4e2a\u5b9a\u65f6\u5668\uff0c\u5f53\u8d85\u8fc7\u6307\u5b9a\u7684\u65f6\u95f4\u540e\uff0c\u6ca1\u6709\u6536\u5230\u5bf9\u65b9\u7684\u00a0<code>ACK<\/code>\u00a0\u786e\u8ba4\u5e94\u7b54\u62a5\u6587\uff0c\u5c31\u4f1a\u91cd\u53d1\u8be5\u6570\u636e\uff0c\u4e5f\u5c31\u662f\u6211\u4eec\u5e38\u8bf4\u7684<strong>\u8d85\u65f6\u91cd\u4f20<\/strong>\u3002<\/p>\n<p>TCP \u4f1a\u5728\u4ee5\u4e0b\u4e24\u79cd\u60c5\u51b5\u53d1\u751f\u8d85\u65f6\u91cd\u4f20\uff1a<\/p>\n<ul>\n<li>\u6570\u636e\u5305\u4e22\u5931<\/li>\n<li>\u786e\u8ba4\u5e94\u7b54\u4e22\u5931<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/4374e501a6f399cf5e310dd7f4999757.png\" alt=\"07c5bae07422516c7c4256bc19fae17b.png\" \/><\/p>\n<blockquote><p>\u8d85\u65f6\u65f6\u95f4\u5e94\u8be5\u8bbe\u7f6e\u4e3a\u591a\u5c11\u5462\uff1f<\/p><\/blockquote>\n<p>\u6211\u4eec\u5148\u6765\u4e86\u89e3\u4e00\u4e0b\u4ec0\u4e48\u662f\u00a0<code>RTT<\/code>\uff08Round-Trip Time \u5f80\u8fd4\u65f6\u5ef6\uff09\uff0c\u4ece\u4e0b\u56fe\u6211\u4eec\u5c31\u53ef\u4ee5\u77e5\u9053\uff1a<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/5c0849df507402dd61f8c0691042d40d.png\" alt=\"RTT\" \/><\/p>\n<p><code>RTT<\/code>\u00a0\u5c31\u662f<strong>\u6570\u636e\u4ece\u7f51\u7edc\u4e00\u7aef\u4f20\u9001\u5230\u53e6\u4e00\u7aef\u6240\u9700\u7684\u65f6\u95f4<\/strong>\uff0c\u4e5f\u5c31\u662f\u5305\u7684\u5f80\u8fd4\u65f6\u95f4\u3002<\/p>\n<p>\u8d85\u65f6\u91cd\u4f20\u65f6\u95f4\u662f\u4ee5\u00a0<code>RTO<\/code>\u00a0\uff08Retransmission Timeout \u8d85\u65f6\u91cd\u4f20\u65f6\u95f4\uff09\u8868\u793a\u3002<\/p>\n<p>\u5047\u8bbe\u5728\u91cd\u4f20\u7684\u60c5\u51b5\u4e0b\uff0c\u8d85\u65f6\u65f6\u95f4\u00a0<code>RTO<\/code>\u00a0\u300c\u8f83\u957f\u6216\u8f83\u77ed\u300d\u65f6\uff0c\u4f1a\u53d1\u751f\u4ec0\u4e48\u4e8b\u60c5\u5462\uff1f<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/32a634b3fc74d9c97eb957175ed11cab.png\" alt=\"0333fbfa25b5d51790ffad2d87cd54d5.png\" \/><\/p>\n<p>\u4e0a\u56fe\u4e2d\u6709\u4e24\u79cd\u8d85\u65f6\u65f6\u95f4\u4e0d\u540c\u7684\u60c5\u51b5\uff1a<\/p>\n<ul>\n<li>\u5f53\u8d85\u65f6\u65f6\u95f4\u00a0<strong>RTO \u8f83\u5927<\/strong>\u65f6\uff0c\u91cd\u53d1\u5c31\u6162\uff0c\u4e22\u4e86\u8001\u534a\u5929\u624d\u91cd\u53d1\uff0c\u6ca1\u6709\u6548\u7387\uff0c\u6027\u80fd\u5dee\uff1b<\/li>\n<li>\u5f53\u8d85\u65f6\u65f6\u95f4\u00a0<strong>RTO \u8f83\u5c0f<\/strong>\u65f6\uff0c\u4f1a\u5bfc\u81f4\u53ef\u80fd\u5e76\u6ca1\u6709\u4e22\u5c31\u91cd\u53d1\uff0c\u4e8e\u662f\u91cd\u53d1\u7684\u5c31\u5feb\uff0c\u4f1a\u589e\u52a0\u7f51\u7edc\u62e5\u585e\uff0c\u5bfc\u81f4\u66f4\u591a\u7684\u8d85\u65f6\uff0c\u66f4\u591a\u7684\u8d85\u65f6\u5bfc\u81f4\u66f4\u591a\u7684\u91cd\u53d1\u3002<\/li>\n<\/ul>\n<p>\u7cbe\u786e\u7684\u6d4b\u91cf\u8d85\u65f6\u65f6\u95f4\u00a0<code>RTO<\/code>\u00a0\u7684\u503c\u662f\u975e\u5e38\u91cd\u8981\u7684\uff0c\u8fd9\u53ef\u8ba9\u6211\u4eec\u7684\u91cd\u4f20\u673a\u5236\u66f4\u9ad8\u6548\u3002<\/p>\n<p>\u6839\u636e\u4e0a\u8ff0\u7684\u4e24\u79cd\u60c5\u51b5\uff0c\u6211\u4eec\u53ef\u4ee5\u5f97\u77e5\uff0c<strong>\u8d85\u65f6\u91cd\u4f20\u65f6\u95f4 RTO \u7684\u503c\u5e94\u8be5\u7565\u5927\u4e8e\u62a5\u6587\u5f80\u8fd4 RTT \u7684\u503c<\/strong>\u3002<\/p>\n<p>\u5b9e\u9645\u4e0a\u300c\u62a5\u6587\u5f80\u8fd4 RTT \u7684\u503c\u300d\u662f\u7ecf\u5e38\u53d8\u5316\u7684\uff0c\u56e0\u4e3a\u6211\u4eec\u7684\u7f51\u7edc\u4e5f\u662f\u65f6\u5e38\u53d8\u5316\u7684\u3002\u4e5f\u5c31\u56e0\u4e3a\u300c\u62a5\u6587\u5f80\u8fd4 RTT \u7684\u503c\u300d \u662f\u7ecf\u5e38\u6ce2\u52a8\u53d8\u5316\u7684\uff0c\u6240\u4ee5\u300c\u8d85\u65f6\u91cd\u4f20\u65f6\u95f4 RTO \u7684\u503c\u300d\u5e94\u8be5\u662f\u4e00\u4e2a<strong>\u52a8\u6001\u53d8\u5316\u7684\u503c<\/strong>\u3002<\/p>\n<h2 id=\"h2-u5FEBu901Fu91CDu4F20\"><a class=\"reference-link\" name=\"\u5feb\u901f\u91cd\u4f20\"><\/a>\u5feb\u901f\u91cd\u4f20<\/h2>\n<p>TCP \u8fd8\u6709\u53e6\u5916\u4e00\u79cd<strong>\u5feb\u901f\u91cd\u4f20\uff08Fast Retransmit\uff09\u673a\u5236<\/strong>\uff0c\u5b83<strong>\u4e0d\u4ee5\u65f6\u95f4\u4e3a\u9a71\u52a8\uff0c\u800c\u662f\u4ee5\u6570\u636e\u9a71\u52a8\u91cd\u4f20<\/strong>\u3002<\/p>\n<p>\u5feb\u901f\u91cd\u4f20\u673a\u5236\uff0c\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u5462\uff1f\u5176\u5b9e\u5f88\u7b80\u5355\uff0c\u4e00\u56fe\u80dc\u5343\u8a00\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/6adfa84aa935615847618ded2affca0b.png\" alt=\"eb55e652d06894f36afcde594c2a3636.png\" \/><\/p>\n<p>\u5728\u4e0a\u56fe\uff0c\u53d1\u9001\u65b9\u53d1\u51fa\u4e86 1\uff0c2\uff0c3\uff0c4\uff0c5 \u4efd\u6570\u636e\uff1a<\/p>\n<ul>\n<li>\u7b2c\u4e00\u4efd Seq1 \u5148\u9001\u5230\u4e86\uff0c\u4e8e\u662f\u5c31 Ack \u56de 2\uff1b<\/li>\n<li>\u7ed3\u679c Seq2 \u56e0\u4e3a\u67d0\u4e9b\u539f\u56e0\u6ca1\u6536\u5230\uff0cSeq3 \u5230\u8fbe\u4e86\uff0c\u4e8e\u662f\u8fd8\u662f Ack \u56de 2\uff1b<\/li>\n<li>\u540e\u9762\u7684 Seq4 \u548c Seq5 \u90fd\u5230\u4e86\uff0c\u4f46\u8fd8\u662f Ack \u56de 2\uff0c\u56e0\u4e3a Seq2 \u8fd8\u662f\u6ca1\u6709\u6536\u5230\uff1b<\/li>\n<li><strong>\u53d1\u9001\u7aef\u6536\u5230\u4e86\u4e09\u4e2a Ack = 2 \u7684\u786e\u8ba4\uff0c\u77e5\u9053\u4e86 Seq2 \u8fd8\u6ca1\u6709\u6536\u5230\uff0c\u5c31\u4f1a\u5728\u5b9a\u65f6\u5668\u8fc7\u671f\u4e4b\u524d\uff0c\u91cd\u4f20\u4e22\u5931\u7684 Seq2\u3002<\/strong><\/li>\n<li>\u6700\u540e\uff0c\u63a5\u6536\u5230\u6536\u5230\u4e86 Seq2\uff0c\u6b64\u65f6\u56e0\u4e3a Seq3\uff0cSeq4\uff0cSeq5 \u90fd\u6536\u5230\u4e86\uff0c\u4e8e\u662f Ack \u56de 6 \u3002<\/li>\n<\/ul>\n<p>\u6240\u4ee5\uff0c\u5feb\u901f\u91cd\u4f20\u7684\u5de5\u4f5c\u65b9\u5f0f\u662f\u5f53\u6536\u5230\u4e09\u4e2a\u76f8\u540c\u7684 ACK \u62a5\u6587\u65f6\uff0c\u4f1a\u5728\u5b9a\u65f6\u5668\u8fc7\u671f\u4e4b\u524d\uff0c\u91cd\u4f20\u4e22\u5931\u7684\u62a5\u6587\u6bb5\u3002<\/p>\n<p>\u5feb\u901f\u91cd\u4f20\u673a\u5236\u53ea\u89e3\u51b3\u4e86\u4e00\u4e2a\u95ee\u9898\uff0c\u5c31\u662f\u8d85\u65f6\u65f6\u95f4\u7684\u95ee\u9898\uff0c\u4f46\u662f\u5b83\u4f9d\u7136\u9762\u4e34\u7740\u53e6\u5916\u4e00\u4e2a\u95ee\u9898\u3002\u5c31\u662f<strong>\u91cd\u4f20\u7684\u65f6\u5019\uff0c\u662f\u91cd\u4f20\u4e4b\u524d\u7684\u4e00\u4e2a\uff0c\u8fd8\u662f\u91cd\u4f20\u6240\u6709\u7684\u95ee\u9898\u3002<\/strong><\/p>\n<p>\u6bd4\u5982\u5bf9\u4e8e\u4e0a\u9762\u7684\u4f8b\u5b50\uff0c\u662f\u91cd\u4f20 Seq2 \u5462\uff1f\u8fd8\u662f\u91cd\u4f20 Seq2\u3001Seq3\u3001Seq4\u3001Seq5 \u5462\uff1f\u56e0\u4e3a\u53d1\u9001\u7aef\u5e76\u4e0d\u6e05\u695a\u8fd9\u8fde\u7eed\u7684\u4e09\u4e2a Ack 2 \u662f\u8c01\u4f20\u56de\u6765\u7684\u3002<\/p>\n<p>\u6839\u636e TCP \u4e0d\u540c\u7684\u5b9e\u73b0\uff0c\u4ee5\u4e0a\u4e24\u79cd\u60c5\u51b5\u90fd\u662f\u6709\u53ef\u80fd\u7684\u3002\u53ef\u89c1\uff0c\u8fd9\u662f\u4e00\u628a\u53cc\u5203\u5251\u3002<\/p>\n<p>\u4e3a\u4e86\u89e3\u51b3\u4e0d\u77e5\u9053\u8be5\u91cd\u4f20\u54ea\u4e9b TCP \u62a5\u6587\uff0c\u4e8e\u662f\u5c31\u6709\u00a0<code>SACK<\/code>\u00a0\u65b9\u6cd5\u3002<\/p>\n<h2 id=\"h2-sack-\"><a class=\"reference-link\" name=\"SACK\u65b9\u6cd5\"><\/a>SACK\u65b9\u6cd5<\/h2>\n<p>\u8fd8\u6709\u4e00\u79cd\u5b9e\u73b0\u91cd\u4f20\u673a\u5236\u7684\u65b9\u5f0f\u53eb\uff1a<code>SACK<\/code>\uff08 Selective Acknowledgment \u9009\u62e9\u6027\u786e\u8ba4\uff09\u3002<\/p>\n<p>\u8fd9\u79cd\u65b9\u5f0f\u9700\u8981\u5728 TCP \u5934\u90e8\u300c\u9009\u9879\u300d\u5b57\u6bb5\u91cc\u52a0\u4e00\u4e2a\u00a0<code>SACK<\/code>\u00a0\u7684\u4e1c\u897f\uff0c\u5b83<strong>\u53ef\u4ee5\u5c06\u7f13\u5b58\u7684\u5730\u56fe\u53d1\u9001\u7ed9\u53d1\u9001\u65b9<\/strong>\uff0c\u8fd9\u6837\u53d1\u9001\u65b9\u5c31\u53ef\u4ee5\u77e5\u9053\u54ea\u4e9b\u6570\u636e\u6536\u5230\u4e86\uff0c\u54ea\u4e9b\u6570\u636e\u6ca1\u6536\u5230\uff0c\u77e5\u9053\u4e86\u8fd9\u4e9b\u4fe1\u606f\uff0c\u5c31\u53ef\u4ee5<strong>\u53ea\u91cd\u4f20\u4e22\u5931\u7684\u6570\u636e<\/strong>\u3002<\/p>\n<p>\u5982\u4e0b\u56fe\uff0c\u53d1\u9001\u65b9\u6536\u5230\u4e86\u4e09\u6b21\u540c\u6837\u7684 ACK \u786e\u8ba4\u62a5\u6587\uff0c\u4e8e\u662f\u5c31\u4f1a\u89e6\u53d1\u5feb\u901f\u91cd\u53d1\u673a\u5236\uff0c\u901a\u8fc7\u00a0<code>SACK<\/code>\u00a0\u4fe1\u606f\u53d1\u73b0\u53ea\u6709\u00a0<code>200~299<\/code>\u00a0\u8fd9\u6bb5\u6570\u636e\u4e22\u5931\uff0c\u5219\u91cd\u53d1\u65f6\uff0c\u5c31\u53ea\u9009\u62e9\u4e86\u8fd9\u4e2a TCP \u6bb5\u8fdb\u884c\u91cd\u590d\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/d76ff80f8654ebf87cce4f3473df64ba.png\" alt=\"4515b0785c783b5f81fa8737ab52396b.png\" \/><\/p>\n<p>\u5982\u679c\u8981\u652f\u6301\u00a0<code>SACK<\/code>\uff0c\u5fc5\u987b\u53cc\u65b9\u90fd\u8981\u652f\u6301\u3002\u5728 Linux \u4e0b\uff0c\u53ef\u4ee5\u901a\u8fc7\u00a0<code>net.ipv4.tcp_sack<\/code>\u00a0\u53c2\u6570\u6253\u5f00\u8fd9\u4e2a\u529f\u80fd\uff08Linux 2.4 \u540e\u9ed8\u8ba4\u6253\u5f00\uff09\u3002<\/p>\n<h2 id=\"h2-duplicate-sack\"><a class=\"reference-link\" name=\"Duplicate SACK\"><\/a>Duplicate SACK<\/h2>\n<p>Duplicate SACK \u53c8\u79f0\u00a0<code>D-SACK<\/code>\uff0c\u5176\u4e3b\u8981<strong>\u4f7f\u7528\u4e86 SACK \u6765\u544a\u8bc9\u300c\u53d1\u9001\u65b9\u300d\u6709\u54ea\u4e9b\u6570\u636e\u88ab\u91cd\u590d\u63a5\u6536\u4e86\u3002<\/strong><\/p>\n<p>\u4e0b\u9762\u4e3e\u4f8b\u4e24\u4e2a\u6817\u5b50\uff0c\u6765\u8bf4\u660e\u00a0<code>D-SACK<\/code>\u00a0\u7684\u4f5c\u7528\u3002<\/p>\n<h3 id=\"h3--em-ack-em-\"><a class=\"reference-link\" style=\"margin: 0px;padding: 0px;background: transparent;color: #4183c4;vertical-align: baseline;text-decoration: none;font-size: 21px;font-family: 'Open Sans', 'Hiragino Sans GB', 'Microsoft YaHei', 'WenQuanYi Micro Hei', Arial, Verdana, Tahoma, sans-serif\" name=\"&lt;em&gt;\u6817\u5b50\u4e00\u53f7\uff1aACK \u4e22\u5305&lt;\/em&gt;\"><\/a><em>\u6817\u5b50\u4e00\u53f7\uff1aACK \u4e22\u5305<\/em><\/h3>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/e27eeb51d1a2c7cd59c0bf9dc5d3f284.png\" alt=\"b2b647c40c08f1f81415044f72808028.png\" \/><\/p>\n<ul>\n<li>\u300c\u63a5\u6536\u65b9\u300d\u53d1\u7ed9\u300c\u53d1\u9001\u65b9\u300d\u7684\u4e24\u4e2a ACK \u786e\u8ba4\u5e94\u7b54\u90fd\u4e22\u5931\u4e86\uff0c\u6240\u4ee5\u53d1\u9001\u65b9\u8d85\u65f6\u540e\uff0c\u91cd\u4f20\u7b2c\u4e00\u4e2a\u6570\u636e\u5305\uff083000 ~ 3499\uff09<\/li>\n<li><strong>\u4e8e\u662f\u300c\u63a5\u6536\u65b9\u300d\u53d1\u73b0\u6570\u636e\u662f\u91cd\u590d\u6536\u5230\u7684\uff0c\u4e8e\u662f\u56de\u4e86\u4e00\u4e2a SACK = 3000~3500<\/strong>\uff0c\u544a\u8bc9\u300c\u53d1\u9001\u65b9\u300d 3000~3500 \u7684\u6570\u636e\u65e9\u5df2\u88ab\u63a5\u6536\u4e86\uff0c\u56e0\u4e3a ACK \u90fd\u5230\u4e86 4000 \u4e86\uff0c\u5df2\u7ecf\u610f\u5473\u7740 4000 \u4e4b\u524d\u7684\u6240\u6709\u6570\u636e\u90fd\u5df2\u6536\u5230\uff0c\u6240\u4ee5\u8fd9\u4e2a SACK \u5c31\u4ee3\u8868\u7740\u00a0<code>D-SACK<\/code>\u3002<\/li>\n<li>\u8fd9\u6837\u300c\u53d1\u9001\u65b9\u300d\u5c31\u77e5\u9053\u4e86\uff0c\u6570\u636e\u6ca1\u6709\u4e22\uff0c\u662f\u300c\u63a5\u6536\u65b9\u300d\u7684 ACK \u786e\u8ba4\u62a5\u6587\u4e22\u4e86\u3002<\/li>\n<\/ul>\n<h3 id=\"h3--em-em-\"><a class=\"reference-link\" style=\"margin: 0px;padding: 0px;background: transparent;color: #4183c4;vertical-align: baseline;text-decoration: none;font-size: 21px;font-family: 'Open Sans', 'Hiragino Sans GB', 'Microsoft YaHei', 'WenQuanYi Micro Hei', Arial, Verdana, Tahoma, sans-serif\" name=\"&lt;em&gt;\u6817\u5b50\u4e8c\u53f7\uff1a\u7f51\u7edc\u5ef6\u65f6&lt;\/em&gt;\"><\/a><em>\u6817\u5b50\u4e8c\u53f7\uff1a\u7f51\u7edc\u5ef6\u65f6<\/em><\/h3>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/1527213f71236b70d07b016287e3b150.png\" alt=\"b92dcf35081f3cdc91950b53a108847a.png\" \/><\/p>\n<ul>\n<li>\u6570\u636e\u5305\uff081000~1499\uff09 \u88ab\u7f51\u7edc\u5ef6\u8fdf\u4e86\uff0c\u5bfc\u81f4\u300c\u53d1\u9001\u65b9\u300d\u6ca1\u6709\u6536\u5230 Ack 1500 \u7684\u786e\u8ba4\u62a5\u6587\u3002<\/li>\n<li>\u800c\u540e\u9762\u62a5\u6587\u5230\u8fbe\u7684\u4e09\u4e2a\u76f8\u540c\u7684 ACK \u786e\u8ba4\u62a5\u6587\uff0c\u5c31\u89e6\u53d1\u4e86\u5feb\u901f\u91cd\u4f20\u673a\u5236\uff0c\u4f46\u662f\u5728\u91cd\u4f20\u540e\uff0c\u88ab\u5ef6\u8fdf\u7684\u6570\u636e\u5305\uff081000~1499\uff09\u53c8\u5230\u4e86\u300c\u63a5\u6536\u65b9\u300d\uff1b<\/li>\n<li><strong>\u6240\u4ee5\u300c\u63a5\u6536\u65b9\u300d\u56de\u4e86\u4e00\u4e2a SACK=1000~1500\uff0c\u56e0\u4e3a ACK \u5df2\u7ecf\u5230\u4e86 3000\uff0c\u6240\u4ee5\u8fd9\u4e2a SACK \u662f D-SACK\uff0c\u8868\u793a\u6536\u5230\u4e86\u91cd\u590d\u7684\u5305\u3002<\/strong><\/li>\n<li>\u8fd9\u6837\u53d1\u9001\u65b9\u5c31\u77e5\u9053\u5feb\u901f\u91cd\u4f20\u89e6\u53d1\u7684\u539f\u56e0\u4e0d\u662f\u53d1\u51fa\u53bb\u7684\u5305\u4e22\u4e86\uff0c\u4e5f\u4e0d\u662f\u56e0\u4e3a\u56de\u5e94\u7684 ACK \u5305\u4e22\u4e86\uff0c\u800c\u662f\u56e0\u4e3a\u7f51\u7edc\u5ef6\u8fdf\u4e86\u3002<\/li>\n<\/ul>\n<p>\u53ef\u89c1\uff0c<code>D-SACK<\/code>\u00a0\u6709\u8fd9\u4e48\u51e0\u4e2a\u597d\u5904\uff1a<\/p>\n<ol>\n<li>\u53ef\u4ee5\u8ba9\u300c\u53d1\u9001\u65b9\u300d\u77e5\u9053\uff0c\u662f\u53d1\u51fa\u53bb\u7684\u5305\u4e22\u4e86\uff0c\u8fd8\u662f\u63a5\u6536\u65b9\u56de\u5e94\u7684 ACK \u5305\u4e22\u4e86;<\/li>\n<li>\u53ef\u4ee5\u77e5\u9053\u662f\u4e0d\u662f\u300c\u53d1\u9001\u65b9\u300d\u7684\u6570\u636e\u5305\u88ab\u7f51\u7edc\u5ef6\u8fdf\u4e86;<\/li>\n<li>\u53ef\u4ee5\u77e5\u9053\u7f51\u7edc\u4e2d\u662f\u4e0d\u662f\u628a\u300c\u53d1\u9001\u65b9\u300d\u7684\u6570\u636e\u5305\u7ed9\u590d\u5236\u4e86;<\/li>\n<\/ol>\n<p>\u5728 Linux \u4e0b\u53ef\u4ee5\u901a\u8fc7\u00a0<code>net.ipv4.tcp_dsack<\/code>\u00a0\u53c2\u6570\u5f00\u542f\/\u5173\u95ed\u8fd9\u4e2a\u529f\u80fd\uff08Linux 2.4 \u540e\u9ed8\u8ba4\u6253\u5f00\uff09\u3002<\/p>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u6ed1\u52a8\u7a97\u53e3\"><\/a>TCP \u6ed1\u52a8\u7a97\u53e3<\/h1>\n<p>\u6211\u4eec\u90fd\u77e5\u9053 TCP \u662f\u6bcf\u53d1\u9001\u4e00\u4e2a\u6570\u636e\uff0c\u90fd\u8981\u8fdb\u884c\u4e00\u6b21\u786e\u8ba4\u5e94\u7b54\u3002\u5f53\u4e0a\u4e00\u4e2a\u6570\u636e\u5305\u6536\u5230\u4e86\u5e94\u7b54\u4e86\uff0c \u518d\u53d1\u9001\u4e0b\u4e00\u4e2a\u3002<\/p>\n<p>\u8fd9\u4e2a\u6a21\u5f0f\u5c31\u6709\u70b9\u50cf\u6211\u548c\u4f60\u9762\u5bf9\u9762\u804a\u5929\uff0c\u4f60\u4e00\u53e5\u6211\u4e00\u53e5\u3002\u4f46\u8fd9\u79cd\u65b9\u5f0f\u7684\u7f3a\u70b9\u662f\u6548\u7387\u6bd4\u8f83\u4f4e\u7684\u3002<\/p>\n<p>\u5982\u679c\u4f60\u8bf4\u5b8c\u4e00\u53e5\u8bdd\uff0c\u6211\u5728\u5904\u7406\u5176\u4ed6\u4e8b\u60c5\uff0c\u6ca1\u6709\u53ca\u65f6\u56de\u590d\u4f60\uff0c\u90a3\u4f60\u4e0d\u662f\u8981\u5e72\u7b49\u7740\u6211\u505a\u5b8c\u5176\u4ed6\u4e8b\u60c5\u540e\uff0c\u6211\u56de\u590d\u4f60\uff0c\u4f60\u624d\u80fd\u8bf4\u4e0b\u4e00\u53e5\u8bdd\uff0c\u5f88\u663e\u7136\u8fd9\u4e0d\u73b0\u5b9e\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/ffe9124d87c4ad71e63ae9bb75aa0cd8.png\" alt=\"c46e4ecaad47cde610eee20642c9cd52.png\" \/><\/p>\n<p>\u6240\u4ee5\uff0c\u8fd9\u6837\u7684\u4f20\u8f93\u65b9\u5f0f\u6709\u4e00\u4e2a\u7f3a\u70b9\uff1a\u6570\u636e\u5305\u7684<strong>\u5f80\u8fd4\u65f6\u95f4\u8d8a\u957f\uff0c\u901a\u4fe1\u7684\u6548\u7387\u5c31\u8d8a\u4f4e<\/strong>\u3002<\/p>\n<p>\u4e3a\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0cTCP \u5f15\u5165\u4e86<strong>\u7a97\u53e3<\/strong>\u8fd9\u4e2a\u6982\u5ff5\u3002\u5373\u4f7f\u5728\u5f80\u8fd4\u65f6\u95f4\u8f83\u957f\u7684\u60c5\u51b5\u4e0b\uff0c\u5b83\u4e5f\u4e0d\u4f1a\u964d\u4f4e\u7f51\u7edc\u901a\u4fe1\u7684\u6548\u7387\u3002<\/p>\n<p>\u90a3\u4e48\u6709\u4e86\u7a97\u53e3\uff0c\u5c31\u53ef\u4ee5\u6307\u5b9a\u7a97\u53e3\u5927\u5c0f\uff0c\u7a97\u53e3\u5927\u5c0f\u5c31\u662f\u6307<strong>\u65e0\u9700\u7b49\u5f85\u786e\u8ba4\u5e94\u7b54\uff0c\u800c\u53ef\u4ee5\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u7684\u6700\u5927\u503c<\/strong>\u3002<\/p>\n<p>\u7a97\u53e3\u7684\u5b9e\u73b0\u5b9e\u9645\u4e0a\u662f\u64cd\u4f5c\u7cfb\u7edf\u5f00\u8f9f\u7684\u4e00\u4e2a\u7f13\u5b58\u7a7a\u95f4\uff0c\u53d1\u9001\u65b9\u4e3b\u673a\u5728\u7b49\u5230\u786e\u8ba4\u5e94\u7b54\u8fd4\u56de\u4e4b\u524d\uff0c\u5fc5\u987b\u5728\u7f13\u51b2\u533a\u4e2d\u4fdd\u7559\u5df2\u53d1\u9001\u7684\u6570\u636e\u3002\u5982\u679c\u6309\u671f\u6536\u5230\u786e\u8ba4\u5e94\u7b54\uff0c\u6b64\u65f6\u6570\u636e\u5c31\u53ef\u4ee5\u4ece\u7f13\u5b58\u533a\u6e05\u9664\u3002<\/p>\n<p>\u5047\u8bbe\u7a97\u53e3\u5927\u5c0f\u4e3a\u00a0<code>3<\/code>\u00a0\u4e2a TCP \u6bb5\uff0c\u90a3\u4e48\u53d1\u9001\u65b9\u5c31\u53ef\u4ee5\u300c\u8fde\u7eed\u53d1\u9001\u300d\u00a0<code>3<\/code>\u00a0\u4e2a TCP \u6bb5\uff0c\u5e76\u4e14\u4e2d\u9014\u82e5\u6709 ACK \u4e22\u5931\uff0c\u53ef\u4ee5\u901a\u8fc7\u300c\u4e0b\u4e00\u4e2a\u786e\u8ba4\u5e94\u7b54\u8fdb\u884c\u786e\u8ba4\u300d\u3002\u5982\u4e0b\u56fe\uff1a<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/408548cb29c295d935cec44acf665f71.png\" alt=\"fc511d0d726bec8a19419d7040b072e8.png\" \/><\/p>\n<p>\u56fe\u4e2d\u7684 ACK 600 \u786e\u8ba4\u5e94\u7b54\u62a5\u6587\u4e22\u5931\uff0c\u4e5f\u6ca1\u5173\u7cfb\uff0c\u56e0\u4e3a\u53ef\u4ee5\u901a\u8bdd\u4e0b\u4e00\u4e2a\u786e\u8ba4\u5e94\u7b54\u8fdb\u884c\u786e\u8ba4\uff0c\u53ea\u8981\u53d1\u9001\u65b9\u6536\u5230\u4e86 ACK 700 \u786e\u8ba4\u5e94\u7b54\uff0c\u5c31\u610f\u5473\u7740 700 \u4e4b\u524d\u7684\u6240\u6709\u6570\u636e\u300c\u63a5\u6536\u65b9\u300d\u90fd\u6536\u5230\u4e86\u3002\u8fd9\u4e2a\u6a21\u5f0f\u5c31\u53eb<strong>\u7d2f\u8ba1\u786e\u8ba4<\/strong>\u6216\u8005<strong>\u7d2f\u8ba1\u5e94\u7b54<\/strong>\u3002<\/p>\n<blockquote><p>\u7a97\u53e3\u5927\u5c0f\u7531\u54ea\u4e00\u65b9\u51b3\u5b9a\uff1f<\/p><\/blockquote>\n<p>TCP \u5934\u91cc\u6709\u4e00\u4e2a\u5b57\u6bb5\u53eb\u00a0<code>Window<\/code>\uff0c\u4e5f\u5c31\u662f\u7a97\u53e3\u5927\u5c0f\u3002<\/p>\n<p><strong>\u8fd9\u4e2a\u5b57\u6bb5\u662f\u63a5\u6536\u7aef\u544a\u8bc9\u53d1\u9001\u7aef\u81ea\u5df1\u8fd8\u6709\u591a\u5c11\u7f13\u51b2\u533a\u53ef\u4ee5\u63a5\u6536\u6570\u636e\u3002\u4e8e\u662f\u53d1\u9001\u7aef\u5c31\u53ef\u4ee5\u6839\u636e\u8fd9\u4e2a\u63a5\u6536\u7aef\u7684\u5904\u7406\u80fd\u529b\u6765\u53d1\u9001\u6570\u636e\uff0c\u800c\u4e0d\u4f1a\u5bfc\u81f4\u63a5\u6536\u7aef\u5904\u7406\u4e0d\u8fc7\u6765\u3002<\/strong><\/p>\n<p>\u6240\u4ee5\uff0c\u901a\u5e38\u7a97\u53e3\u7684\u5927\u5c0f\u662f\u7531\u63a5\u6536\u65b9\u7684\u51b3\u5b9a\u7684\u3002<\/p>\n<p>\u53d1\u9001\u65b9\u53d1\u9001\u7684\u6570\u636e\u5927\u5c0f\u4e0d\u80fd\u8d85\u8fc7\u63a5\u6536\u65b9\u7684\u7a97\u53e3\u5927\u5c0f\uff0c\u5426\u5219\u63a5\u6536\u65b9\u5c31\u65e0\u6cd5\u6b63\u5e38\u63a5\u6536\u5230\u6570\u636e\u3002<\/p>\n<blockquote><p>\u53d1\u9001\u65b9\u7684\u6ed1\u52a8\u7a97\u53e3<\/p><\/blockquote>\n<p>\u6211\u4eec\u5148\u6765\u770b\u770b\u53d1\u9001\u65b9\u7684\u7a97\u53e3\uff0c\u4e0b\u56fe\u5c31\u662f\u53d1\u9001\u65b9\u7f13\u5b58\u7684\u6570\u636e\uff0c\u6839\u636e\u5904\u7406\u7684\u60c5\u51b5\u5206\u6210\u56db\u4e2a\u90e8\u5206\uff0c\u5176\u4e2d\u6df1\u84dd\u8272\u65b9\u6846\u662f\u53d1\u9001\u7a97\u53e3\uff0c\u7d2b\u8272\u65b9\u6846\u662f\u53ef\u7528\u7a97\u53e3\uff1a<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/1088a2e20d4ab9ef4ed5a20cee588059.png\" alt=\"e64134cb96d59ef73d3f4c7037e93e92.png\" \/><\/p>\n<ul>\n<li>#1 \u662f\u5df2\u53d1\u9001\u5e76\u6536\u5230 ACK\u786e\u8ba4\u7684\u6570\u636e\uff1a1~31 \u5b57\u8282<\/li>\n<li>#2 \u662f\u5df2\u53d1\u9001\u4f46\u672a\u6536\u5230 ACK\u786e\u8ba4\u7684\u6570\u636e\uff1a32~45 \u5b57\u8282<\/li>\n<li>#3 \u662f\u672a\u53d1\u9001\u4f46\u603b\u5927\u5c0f\u5728\u63a5\u6536\u65b9\u5904\u7406\u8303\u56f4\u5185\uff08\u63a5\u6536\u65b9\u8fd8\u6709\u7a7a\u95f4\uff09\uff1a46~51\u5b57\u8282<\/li>\n<li>#4 \u662f\u672a\u53d1\u9001\u4f46\u603b\u5927\u5c0f\u8d85\u8fc7\u63a5\u6536\u65b9\u5904\u7406\u8303\u56f4\uff08\u63a5\u6536\u65b9\u6ca1\u6709\u7a7a\u95f4\uff09\uff1a52\u5b57\u8282\u4ee5\u540e<\/li>\n<\/ul>\n<p>\u5728\u4e0b\u56fe\uff0c\u5f53\u53d1\u9001\u65b9\u628a\u6570\u636e\u300c\u5168\u90e8\u300d\u90fd\u4e00\u4e0b\u53d1\u9001\u51fa\u53bb\u540e\uff0c\u53ef\u7528\u7a97\u53e3\u7684\u5927\u5c0f\u5c31\u4e3a 0 \u4e86\uff0c\u8868\u660e\u53ef\u7528\u7a97\u53e3\u8017\u5c3d\uff0c\u5728\u6ca1\u6536\u5230 ACK \u786e\u8ba4\u4e4b\u524d\u662f\u65e0\u6cd5\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u4e86\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/fa0e792fa1dffb245ef2bcca54ebb7ce.png\" alt=\"fe3da3955b0c297efaa3f98cb6d57028.png\" \/><\/p>\n<p>\u5728\u4e0b\u56fe\uff0c\u5f53\u6536\u5230\u4e4b\u524d\u53d1\u9001\u7684\u6570\u636e\u00a0<code>32~36<\/code>\u00a0\u5b57\u8282\u7684 ACK \u786e\u8ba4\u5e94\u7b54\u540e\uff0c\u5982\u679c\u53d1\u9001\u7a97\u53e3\u7684\u5927\u5c0f\u6ca1\u6709\u53d8\u5316\uff0c\u5219<strong>\u6ed1\u52a8\u7a97\u53e3\u5f80\u53f3\u8fb9\u79fb\u52a8 5 \u4e2a\u5b57\u8282\uff0c\u56e0\u4e3a\u6709 5 \u4e2a\u5b57\u8282\u7684\u6570\u636e\u88ab\u5e94\u7b54\u786e\u8ba4<\/strong>\uff0c\u63a5\u4e0b\u6765\u00a0<code>52~56<\/code>\u00a0\u5b57\u8282\u53c8\u53d8\u6210\u4e86\u53ef\u7528\u7a97\u53e3\uff0c\u90a3\u4e48\u540e\u7eed\u4e5f\u5c31\u53ef\u4ee5\u53d1\u9001\u00a0<code>52~56<\/code>\u00a0\u8fd9 5 \u4e2a\u5b57\u8282\u7684\u6570\u636e\u4e86\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/5c8636819fc464499a3568a5869bbc43.png\" alt=\"d408d008d2a05643f049856f8a181d30.png\" \/><\/p>\n<blockquote><p>\u7a0b\u5e8f\u662f\u5982\u4f55\u8868\u793a\u53d1\u9001\u65b9\u7684\u56db\u4e2a\u90e8\u5206\u7684\u5462\uff1f<\/p><\/blockquote>\n<p>TCP \u6ed1\u52a8\u7a97\u53e3\u65b9\u6848\u4f7f\u7528\u4e09\u4e2a\u6307\u9488\u6765\u8ddf\u8e2a\u5728\u56db\u4e2a\u4f20\u8f93\u7c7b\u522b\u4e2d\u7684\u6bcf\u4e00\u4e2a\u7c7b\u522b\u4e2d\u7684\u5b57\u8282\u3002\u5176\u4e2d\u4e24\u4e2a\u6307\u9488\u662f\u7edd\u5bf9\u6307\u9488\uff08\u6307\u7279\u5b9a\u7684\u5e8f\u5217\u53f7\uff09\uff0c\u4e00\u4e2a\u662f\u76f8\u5bf9\u6307\u9488\uff08\u9700\u8981\u505a\u504f\u79fb\uff09\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/d698c7fd8b3c0a95b6b886760ab405ef.png\" alt=\"8170032d0922f46d466871328c60cccc.png\" \/><\/p>\n<ul>\n<li><code>SND.WND<\/code>\uff1a\u8868\u793a\u53d1\u9001\u7a97\u53e3\u7684\u5927\u5c0f\uff08\u5927\u5c0f\u662f\u7531\u63a5\u6536\u65b9\u6307\u5b9a\u7684\uff09\uff1b<\/li>\n<li><code>SND.UNA<\/code>\uff1a\u662f\u4e00\u4e2a\u7edd\u5bf9\u6307\u9488\uff0c\u5b83\u6307\u5411\u7684\u662f\u5df2\u53d1\u9001\u4f46\u672a\u6536\u5230\u786e\u8ba4\u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u5e8f\u5217\u53f7\uff0c\u4e5f\u5c31\u662f #2 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u3002<\/li>\n<li><code>SND.NXT<\/code>\uff1a\u4e5f\u662f\u4e00\u4e2a\u7edd\u5bf9\u6307\u9488\uff0c\u5b83\u6307\u5411\u672a\u53d1\u9001\u4f46\u53ef\u53d1\u9001\u8303\u56f4\u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u5e8f\u5217\u53f7\uff0c\u4e5f\u5c31\u662f #3 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u3002<\/li>\n<li>\u6307\u5411 #4 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u662f\u4e2a\u76f8\u5bf9\u6307\u9488\uff0c\u5b83\u9700\u8981\u00a0<code>SND.NXT<\/code>\u00a0\u6307\u9488\u52a0\u4e0a\u00a0<code>SND.WND<\/code>\u00a0\u5927\u5c0f\u7684\u504f\u79fb\u91cf\uff0c\u5c31\u53ef\u4ee5\u6307\u5411 #4 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u4e86\u3002<\/li>\n<\/ul>\n<p>\u90a3\u4e48\u53ef\u7528\u7a97\u53e3\u5927\u5c0f\u7684\u8ba1\u7b97\u5c31\u53ef\u4ee5\u662f\uff1a<\/p>\n<p><strong>\u53ef\u7528\u7a97\u53e3\u5927 = SND.WND -\uff08SND.NXT - SND.UNA\uff09<\/strong><\/p>\n<blockquote><p>\u63a5\u6536\u65b9\u7684\u6ed1\u52a8\u7a97\u53e3<\/p><\/blockquote>\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u770b\u770b\u63a5\u6536\u65b9\u7684\u7a97\u53e3\uff0c\u63a5\u6536\u7a97\u53e3\u76f8\u5bf9\u7b80\u5355\u4e00\u4e9b\uff0c\u6839\u636e\u5904\u7406\u7684\u60c5\u51b5\u5212\u5206\u6210\u4e09\u4e2a\u90e8\u5206\uff1aTCP \u6d41\u91cf\u63a7\u5236<\/p>\n<p>\u6d41\u91cf\u63a7\u5236\u662f\u4e3a\u4e86\u63a7\u5236\u53d1\u9001\u65b9\u53d1\u9001\u901f\u7387\uff0c\u4fdd\u8bc1\u63a5\u6536\u65b9\u6765\u5f97\u53ca\u63a5\u6536\u3002<\/p>\n<p>\u63a5\u6536\u65b9\u53d1\u9001\u7684\u786e\u8ba4\u62a5\u6587\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\u53ef\u4ee5\u7528\u6765\u63a7\u5236\u53d1\u9001\u65b9\u7a97\u53e3\u5927\u5c0f\uff0c\u4ece\u800c\u5f71\u54cd\u53d1\u9001\u65b9\u7684\u53d1\u9001\u901f\u7387\u3002\u5c06\u7a97\u53e3\u5b57\u6bb5\u8bbe\u7f6e\u4e3a 0\uff0c\u5219\u53d1\u9001\u65b9\u4e0d\u80fd\u53d1\u9001\u6570\u636e\u3002<\/p>\n<ul>\n<li>#1 + #2 \u662f\u5df2\u6210\u529f\u63a5\u6536\u5e76\u786e\u8ba4\u7684\u6570\u636e\uff08\u7b49\u5f85\u5e94\u7528\u8fdb\u7a0b\u8bfb\u53d6\uff09\uff1b<\/li>\n<li>#3 \u662f\u672a\u6536\u5230\u6570\u636e\u4f46\u53ef\u4ee5\u63a5\u6536\u7684\u6570\u636e\uff1b<\/li>\n<li>#4 \u672a\u6536\u5230\u6570\u636e\u5e76\u4e0d\u53ef\u4ee5\u63a5\u6536\u7684\u6570\u636e\uff1b<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/48d10b5933797f421cd2e9925ce44deb.png\" alt=\"c8b42c08d27a80e34644a384a7dc3b49.png\" \/><\/p>\n<p>\u5176\u4e2d\u4e09\u4e2a\u63a5\u6536\u90e8\u5206\uff0c\u4f7f\u7528\u4e24\u4e2a\u6307\u9488\u8fdb\u884c\u5212\u5206:<\/p>\n<ul>\n<li><code>RCV.WND<\/code>\uff1a\u8868\u793a\u63a5\u6536\u7a97\u53e3\u7684\u5927\u5c0f\uff0c\u5b83\u4f1a\u901a\u544a\u7ed9\u53d1\u9001\u65b9\u3002<\/li>\n<li><code>RCV.NXT<\/code>\uff1a\u662f\u4e00\u4e2a\u6307\u9488\uff0c\u5b83\u6307\u5411\u671f\u671b\u4ece\u53d1\u9001\u65b9\u53d1\u9001\u6765\u7684\u4e0b\u4e00\u4e2a\u6570\u636e\u5b57\u8282\u7684\u5e8f\u5217\u53f7\uff0c\u4e5f\u5c31\u662f #3 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u3002<\/li>\n<li>\u6307\u5411 #4 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u662f\u4e2a\u76f8\u5bf9\u6307\u9488\uff0c\u5b83\u9700\u8981\u00a0<code>RCV.NXT<\/code>\u00a0\u6307\u9488\u52a0\u4e0a\u00a0<code>RCV.WND<\/code>\u00a0\u5927\u5c0f\u7684\u504f\u79fb\u91cf\uff0c\u5c31\u53ef\u4ee5\u6307\u5411 #4 \u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u4e86\u3002<\/li>\n<\/ul>\n<blockquote><p>\u63a5\u6536\u7a97\u53e3\u548c\u53d1\u9001\u7a97\u53e3\u7684\u5927\u5c0f\u662f\u76f8\u7b49\u7684\u5417\uff1f<\/p><\/blockquote>\n<p>\u5e76\u4e0d\u662f\u5b8c\u5168\u76f8\u7b49\uff0c\u63a5\u6536\u7a97\u53e3\u7684\u5927\u5c0f\u662f<strong>\u7ea6\u7b49\u4e8e<\/strong>\u53d1\u9001\u7a97\u53e3\u7684\u5927\u5c0f\u7684\u3002<\/p>\n<p>\u56e0\u4e3a\u6ed1\u52a8\u7a97\u53e3\u5e76\u4e0d\u662f\u4e00\u6210\u4e0d\u53d8\u7684\u3002\u6bd4\u5982\uff0c\u5f53\u63a5\u6536\u65b9\u7684\u5e94\u7528\u8fdb\u7a0b\u8bfb\u53d6\u6570\u636e\u7684\u901f\u5ea6\u975e\u5e38\u5feb\u7684\u8bdd\uff0c\u8fd9\u6837\u7684\u8bdd\u63a5\u6536\u7a97\u53e3\u53ef\u4ee5\u5f88\u5feb\u7684\u5c31\u7a7a\u7f3a\u51fa\u6765\u3002\u90a3\u4e48\u65b0\u7684\u63a5\u6536\u7a97\u53e3\u5927\u5c0f\uff0c\u662f\u901a\u8fc7 TCP \u62a5\u6587\u4e2d\u7684 Windows \u5b57\u6bb5\u6765\u544a\u8bc9\u53d1\u9001\u65b9\u3002\u90a3\u4e48\u8fd9\u4e2a\u4f20\u8f93\u8fc7\u7a0b\u662f\u5b58\u5728\u65f6\u5ef6\u7684\uff0c\u6240\u4ee5\u63a5\u6536\u7a97\u53e3\u548c\u53d1\u9001\u7a97\u53e3\u662f\u7ea6\u7b49\u4e8e\u7684\u5173\u7cfb\u3002<\/p>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u6d41\u91cf\u63a7\u5236\"><\/a>TCP \u6d41\u91cf\u63a7\u5236<\/h1>\n<p>\u53d1\u9001\u65b9\u4e0d\u80fd\u65e0\u8111\u7684\u53d1\u6570\u636e\u7ed9\u63a5\u6536\u65b9\uff0c\u8981\u8003\u8651\u63a5\u6536\u65b9\u5904\u7406\u80fd\u529b\u3002<\/p>\n<p>\u5982\u679c\u4e00\u76f4\u65e0\u8111\u7684\u53d1\u6570\u636e\u7ed9\u5bf9\u65b9\uff0c\u4f46\u5bf9\u65b9\u5904\u7406\u4e0d\u8fc7\u6765\uff0c\u90a3\u4e48\u5c31\u4f1a\u5bfc\u81f4\u89e6\u53d1\u91cd\u53d1\u673a\u5236\uff0c\u4ece\u800c\u5bfc\u81f4\u7f51\u7edc\u6d41\u91cf\u7684\u65e0\u7aef\u7684\u6d6a\u8d39\u3002<\/p>\n<p>\u4e3a\u4e86\u89e3\u51b3\u8fd9\u79cd\u73b0\u8c61\u53d1\u751f\uff0c<strong>TCP \u63d0\u4f9b\u4e00\u79cd\u673a\u5236\u53ef\u4ee5\u8ba9\u300c\u53d1\u9001\u65b9\u300d\u6839\u636e\u300c\u63a5\u6536\u65b9\u300d\u7684\u5b9e\u9645\u63a5\u6536\u80fd\u529b\u63a7\u5236\u53d1\u9001\u7684\u6570\u636e\u91cf\uff0c\u8fd9\u5c31\u662f\u6240\u8c13\u7684\u6d41\u91cf\u63a7\u5236\u3002<\/strong><\/p>\n<p>\u4e0b\u9762\u4e3e\u4e2a\u6817\u5b50\uff0c\u4e3a\u4e86\u7b80\u5355\u8d77\u89c1\uff0c\u5047\u8bbe\u4ee5\u4e0b\u573a\u666f\uff1a<\/p>\n<ul>\n<li>\u5ba2\u6237\u7aef\u662f\u63a5\u6536\u65b9\uff0c\u670d\u52a1\u7aef\u662f\u53d1\u9001\u65b9<\/li>\n<li>\u5047\u8bbe\u63a5\u6536\u7a97\u53e3\u548c\u53d1\u9001\u7a97\u53e3\u76f8\u540c\uff0c\u90fd\u4e3a\u00a0<code>200<\/code><\/li>\n<li>\u5047\u8bbe\u4e24\u4e2a\u8bbe\u5907\u5728\u6574\u4e2a\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u90fd\u4fdd\u6301\u76f8\u540c\u7684\u7a97\u53e3\u5927\u5c0f\uff0c\u4e0d\u53d7\u5916\u754c\u5f71\u54cd<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/a91989c080671195b1ccee62aa46b570.png\" alt=\"c8e75472e3c79b9e9f320372d211b738.png\" \/><\/p>\n<p>\u6839\u636e\u4e0a\u56fe\u7684\u6d41\u91cf\u63a7\u5236\uff0c\u8bf4\u660e\u4e0b\u6bcf\u4e2a\u8fc7\u7a0b\uff1a<\/p>\n<ol>\n<li>\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u7aef\u53d1\u9001\u8bf7\u6c42\u6570\u636e\u62a5\u6587\u3002\u8fd9\u91cc\u8981\u8bf4\u660e\u4e0b\uff0c\u672c\u6b21\u4f8b\u5b50\u662f\u628a\u670d\u52a1\u7aef\u4f5c\u4e3a\u53d1\u9001\u65b9\uff0c\u6240\u4ee5\u6ca1\u6709\u753b\u51fa\u670d\u52a1\u7aef\u7684\u63a5\u6536\u7a97\u53e3\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230\u8bf7\u6c42\u62a5\u6587\u540e\uff0c\u53d1\u9001\u786e\u8ba4\u62a5\u6587\u548c 80 \u5b57\u8282\u7684\u6570\u636e\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u00a0<code>Usable<\/code>\u00a0\u51cf\u5c11\u4e3a 120 \u5b57\u8282\uff0c\u540c\u65f6\u00a0<code>SND.NXT<\/code>\u00a0\u6307\u9488\u4e5f\u5411\u53f3\u504f\u79fb 80 \u5b57\u8282\u540e\uff0c\u6307\u5411 321\uff0c<strong>\u8fd9\u610f\u5473\u7740\u4e0b\u6b21\u53d1\u9001\u6570\u636e\u7684\u65f6\u5019\uff0c\u5e8f\u5217\u53f7\u662f 321\u3002<\/strong><\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230 80 \u5b57\u8282\u6570\u636e\u540e\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u5f80\u53f3\u79fb\u52a8 80 \u5b57\u8282\uff0c<code>RCV.NXT<\/code>\u00a0\u4e5f\u5c31\u6307\u5411 321\uff0c<strong>\u8fd9\u610f\u5473\u7740\u5ba2\u6237\u7aef\u671f\u671b\u7684\u4e0b\u4e00\u4e2a\u62a5\u6587\u7684\u5e8f\u5217\u53f7\u662f 321<\/strong>\uff0c\u63a5\u7740\u53d1\u9001\u786e\u8ba4\u62a5\u6587\u7ed9\u670d\u52a1\u7aef\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u518d\u6b21\u53d1\u9001\u4e86 120 \u5b57\u8282\u6570\u636e\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u8017\u5c3d\u4e3a 0\uff0c\u670d\u52a1\u7aef\u65e0\u6cd5\u5728\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230 120 \u5b57\u8282\u7684\u6570\u636e\u540e\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u5f80\u53f3\u79fb\u52a8 120 \u5b57\u8282\uff0c<code>RCV.NXT<\/code>\u00a0\u4e5f\u5c31\u6307\u5411 441\uff0c\u63a5\u7740\u53d1\u9001\u786e\u8ba4\u62a5\u6587\u7ed9\u670d\u52a1\u7aef\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230\u5bf9 80 \u5b57\u8282\u6570\u636e\u7684\u786e\u8ba4\u62a5\u6587\u540e\uff0c<code>SND.UNA<\/code>\u00a0\u6307\u9488\u5f80\u53f3\u504f\u79fb\u540e\u6307\u5411 321\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u00a0<code>Usable<\/code>\u00a0\u589e\u5927\u5230 80\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230\u5bf9 120 \u5b57\u8282\u6570\u636e\u7684\u786e\u8ba4\u62a5\u6587\u540e\uff0c<code>SND.UNA<\/code>\u00a0\u6307\u9488\u5f80\u53f3\u504f\u79fb\u540e\u6307\u5411 441\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u00a0<code>Usable<\/code>\u00a0\u589e\u5927\u5230 200\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u53ef\u4ee5\u7ee7\u7eed\u53d1\u9001\u4e86\uff0c\u4e8e\u662f\u53d1\u9001\u4e86 160 \u5b57\u8282\u7684\u6570\u636e\u540e\uff0c<code>SND.NXT<\/code>\u00a0\u6307\u5411 601\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u00a0<code>Usable<\/code>\u00a0\u51cf\u5c11\u5230 40\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230 160 \u5b57\u8282\u540e\uff0c\u63a5\u6536\u7a97\u53e3\u5f80\u53f3\u79fb\u52a8\u4e86 160 \u5b57\u8282\uff0c<code>RCV.NXT<\/code>\u00a0\u4e5f\u5c31\u662f\u6307\u5411\u4e86 601\uff0c\u63a5\u7740\u53d1\u9001\u786e\u8ba4\u62a5\u6587\u7ed9\u670d\u52a1\u7aef\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230\u5bf9 160 \u5b57\u8282\u6570\u636e\u7684\u786e\u8ba4\u62a5\u6587\u540e\uff0c\u53d1\u9001\u7a97\u53e3\u5f80\u53f3\u79fb\u52a8\u4e86 160 \u5b57\u8282\uff0c\u4e8e\u662f\u00a0<code>SND.UNA<\/code>\u00a0\u6307\u9488\u504f\u79fb\u4e86 160 \u540e\u6307\u5411 601\uff0c\u53ef\u7528\u7a97\u53e3\u00a0<code>Usable<\/code>\u00a0\u4e5f\u5c31\u589e\u5927\u81f3\u4e86 200\u3002<\/li>\n<\/ol>\n<h2 id=\"h2-u64CDu4F5Cu7CFBu7EDFu7F13u51B2u533Au4E0Eu6ED1u52A8u7A97u53E3u7684u5173u7CFB\"><a class=\"reference-link\" name=\"\u64cd\u4f5c\u7cfb\u7edf\u7f13\u51b2\u533a\u4e0e\u6ed1\u52a8\u7a97\u53e3\u7684\u5173\u7cfb\"><\/a>\u64cd\u4f5c\u7cfb\u7edf\u7f13\u51b2\u533a\u4e0e\u6ed1\u52a8\u7a97\u53e3\u7684\u5173\u7cfb<\/h2>\n<p>\u524d\u9762\u7684\u6d41\u91cf\u63a7\u5236\u4f8b\u5b50\uff0c\u6211\u4eec\u5047\u5b9a\u4e86\u53d1\u9001\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u662f\u4e0d\u53d8\u7684\uff0c\u4f46\u662f\u5b9e\u9645\u4e0a\uff0c\u53d1\u9001\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u4e2d\u6240\u5b58\u653e\u7684\u5b57\u8282\u6570\uff0c\u90fd\u662f\u653e\u5728\u64cd\u4f5c\u7cfb\u7edf\u5185\u5b58\u7f13\u51b2\u533a\u4e2d\u7684\uff0c\u800c\u64cd\u4f5c\u7cfb\u7edf\u7684\u7f13\u51b2\u533a\uff0c\u4f1a<strong>\u88ab\u64cd\u4f5c\u7cfb\u7edf\u8c03\u6574<\/strong>\u3002<\/p>\n<p>\u5f53\u5e94\u7528\u8fdb\u7a0b\u6ca1\u529e\u6cd5\u53ca\u65f6\u8bfb\u53d6\u7f13\u51b2\u533a\u7684\u5185\u5bb9\u65f6\uff0c\u4e5f\u4f1a\u5bf9\u6211\u4eec\u7684\u7f13\u51b2\u533a\u9020\u6210\u5f71\u54cd\u3002<\/p>\n<blockquote><p>\u90a3\u64cd\u5fc3\u7cfb\u7edf\u7684\u7f13\u51b2\u533a\uff0c\u662f\u5982\u4f55\u5f71\u54cd\u53d1\u9001\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u7684\u5462\uff1f<\/p><\/blockquote>\n<p><em>\u6211\u4eec\u5148\u6765\u770b\u770b\u7b2c\u4e00\u4e2a\u4f8b\u5b50\u3002<\/em><\/p>\n<p>\u5f53\u5e94\u7528\u7a0b\u5e8f\u6ca1\u6709\u53ca\u65f6\u8bfb\u53d6\u7f13\u5b58\u65f6\uff0c\u53d1\u9001\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u7684\u53d8\u5316\u3002<\/p>\n<p>\u8003\u8651\u4ee5\u4e0b\u573a\u666f\uff1a<\/p>\n<ul>\n<li>\u5ba2\u6237\u7aef\u4f5c\u4e3a\u53d1\u9001\u65b9\uff0c\u670d\u52a1\u7aef\u4f5c\u4e3a\u63a5\u6536\u65b9\uff0c\u53d1\u9001\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u521d\u59cb\u5927\u5c0f\u4e3a\u00a0<code>360<\/code>\uff1b<\/li>\n<li>\u670d\u52a1\u7aef\u975e\u5e38\u7684\u7e41\u5fd9\uff0c\u5f53\u6536\u5230\u5ba2\u6237\u7aef\u7684\u6570\u636e\u65f6\uff0c\u5e94\u7528\u5c42\u4e0d\u80fd\u53ca\u65f6\u8bfb\u53d6\u6570\u636e\u3002<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/a1db15d797779a75b7d816c4afd782f9.png\" alt=\"e3f5887b5a916096db20e27e6f02291c.png\" \/><\/p>\n<p>\u6839\u636e\u4e0a\u56fe\u7684\u6d41\u91cf\u63a7\u5236\uff0c\u8bf4\u660e\u4e0b\u6bcf\u4e2a\u8fc7\u7a0b\uff1a<\/p>\n<ol>\n<li>\u5ba2\u6237\u7aef\u53d1\u9001 140 \u5b57\u8282\u6570\u636e\u540e\uff0c\u53ef\u7528\u7a97\u53e3\u53d8\u4e3a 220 \uff08360 - 140\uff09\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230 140 \u5b57\u8282\u6570\u636e\uff0c<strong>\u4f46\u662f\u670d\u52a1\u7aef\u975e\u5e38\u7e41\u5fd9\uff0c\u5e94\u7528\u8fdb\u7a0b\u53ea\u8bfb\u53d6\u4e86 40 \u4e2a\u5b57\u8282\uff0c\u8fd8\u6709 100 \u5b57\u8282\u5360\u7528\u7740\u7f13\u51b2\u533a\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u6536\u7f29\u5230\u4e86 260 \uff08360 - 100\uff09<\/strong>\uff0c\u6700\u540e\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u65f6\uff0c\u5c06\u7a97\u53e3\u5927\u5c0f\u901a\u8fc7\u7ed9\u5ba2\u6237\u7aef\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230\u786e\u8ba4\u548c\u7a97\u53e3\u901a\u544a\u62a5\u6587\u540e\uff0c\u53d1\u9001\u7a97\u53e3\u51cf\u5c11\u4e3a 260\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u53d1\u9001 180 \u5b57\u8282\u6570\u636e\uff0c\u6b64\u65f6\u53ef\u7528\u7a97\u53e3\u51cf\u5c11\u5230 80\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230 180 \u5b57\u8282\u6570\u636e\uff0c<strong>\u4f46\u662f\u5e94\u7528\u7a0b\u5e8f\u6ca1\u6709\u8bfb\u53d6\u4efb\u4f55\u6570\u636e\uff0c\u8fd9 180 \u5b57\u8282\u76f4\u63a5\u5c31\u7559\u5728\u4e86\u7f13\u51b2\u533a\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u6536\u7f29\u5230\u4e86 80 \uff08260 - 180\uff09<\/strong>\uff0c\u5e76\u5728\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u65f6\uff0c\u901a\u8fc7\u7a97\u53e3\u5927\u5c0f\u7ed9\u5ba2\u6237\u7aef\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230\u786e\u8ba4\u548c\u7a97\u53e3\u901a\u544a\u62a5\u6587\u540e\uff0c\u53d1\u9001\u7a97\u53e3\u51cf\u5c11\u4e3a 80\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u53d1\u9001 80 \u5b57\u8282\u6570\u636e\u540e\uff0c\u53ef\u7528\u7a97\u53e3\u8017\u5c3d\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230 80 \u5b57\u8282\u6570\u636e\uff0c<strong>\u4f46\u662f\u5e94\u7528\u7a0b\u5e8f\u4f9d\u7136\u6ca1\u6709\u8bfb\u53d6\u4efb\u4f55\u6570\u636e\uff0c\u8fd9 80 \u5b57\u8282\u7559\u5728\u4e86\u7f13\u51b2\u533a\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u6536\u7f29\u5230\u4e86 0<\/strong>\uff0c\u5e76\u5728\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u65f6\uff0c\u901a\u8fc7\u7a97\u53e3\u5927\u5c0f\u7ed9\u5ba2\u6237\u7aef\u3002<\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230\u786e\u8ba4\u548c\u7a97\u53e3\u901a\u544a\u62a5\u6587\u540e\uff0c\u53d1\u9001\u7a97\u53e3\u51cf\u5c11\u4e3a 0\u3002<\/li>\n<\/ol>\n<p>\u53ef\u89c1\u6700\u540e\u7a97\u53e3\u90fd\u6536\u7f29\u4e3a 0 \u4e86\uff0c\u4e5f\u5c31\u662f\u53d1\u751f\u4e86\u7a97\u53e3\u5173\u95ed\u3002\u5f53\u53d1\u9001\u65b9\u53ef\u7528\u7a97\u53e3\u53d8\u4e3a 0 \u65f6\uff0c\u53d1\u9001\u65b9\u5b9e\u9645\u4e0a\u4f1a\u5b9a\u65f6\u53d1\u9001\u7a97\u53e3\u63a2\u6d4b\u62a5\u6587\uff0c\u4ee5\u4fbf\u77e5\u9053\u63a5\u6536\u65b9\u7684\u7a97\u53e3\u662f\u5426\u53d1\u751f\u4e86\u6539\u53d8\uff0c\u8fd9\u4e2a\u5185\u5bb9\u540e\u9762\u4f1a\u8bf4\uff0c\u8fd9\u91cc\u5148\u7b80\u5355\u63d0\u4e00\u4e0b\u3002<\/p>\n<p><em>\u6211\u4eec\u5148\u6765\u770b\u770b\u7b2c\u4e8c\u4e2a\u4f8b\u5b50\u3002<\/em><\/p>\n<p>\u5f53\u670d\u52a1\u7aef\u7cfb\u7edf\u8d44\u6e90\u975e\u5e38\u7d27\u5f20\u7684\u65f6\u5019\uff0c\u64cd\u5fc3\u7cfb\u7edf\u53ef\u80fd\u4f1a\u76f4\u63a5\u51cf\u5c11\u4e86\u63a5\u6536\u7f13\u51b2\u533a\u5927\u5c0f\uff0c\u8fd9\u65f6\u5e94\u7528\u7a0b\u5e8f\u53c8\u65e0\u6cd5\u53ca\u65f6\u8bfb\u53d6\u7f13\u5b58\u6570\u636e\uff0c\u90a3\u4e48\u8fd9\u65f6\u5019\u5c31\u6709\u4e25\u91cd\u7684\u4e8b\u60c5\u53d1\u751f\u4e86\uff0c\u4f1a\u51fa\u73b0\u6570\u636e\u5305\u4e22\u5931\u7684\u73b0\u8c61\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/9385e62e8028964123f51d183d4de637.png\" alt=\"a1ea906017428063ceee90e95494c45a.png\" \/><\/p>\n<p>\u8bf4\u660e\u4e0b\u6bcf\u4e2a\u8fc7\u7a0b\uff1a<\/p>\n<ol>\n<li>\u5ba2\u6237\u7aef\u53d1\u9001 140 \u5b57\u8282\u7684\u6570\u636e\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u51cf\u5c11\u5230\u4e86 220\u3002<\/li>\n<li><strong>\u670d\u52a1\u7aef\u56e0\u4e3a\u73b0\u5728\u975e\u5e38\u7684\u7e41\u5fd9\uff0c\u64cd\u4f5c\u7cfb\u7edf\u4e8e\u662f\u5c31\u628a\u63a5\u6536\u7f13\u5b58\u51cf\u5c11\u4e86 100 \u5b57\u8282\uff0c\u5f53\u6536\u5230 \u5bf9 140 \u6570\u636e\u786e\u8ba4\u62a5\u6587\u540e\uff0c\u53c8\u56e0\u4e3a\u5e94\u7528\u7a0b\u5e8f\u6ca1\u6709\u8bfb\u53d6\u4efb\u4f55\u6570\u636e\uff0c\u6240\u4ee5 140 \u5b57\u8282\u7559\u5728\u4e86\u7f13\u51b2\u533a\u4e2d\uff0c\u4e8e\u662f\u63a5\u6536\u7a97\u53e3\u5927\u5c0f\u4ece 360 \u6536\u7f29\u6210\u4e86 100<\/strong>\uff0c\u6700\u540e\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u65f6\uff0c\u901a\u544a\u7a97\u53e3\u5927\u5c0f\u7ed9\u5bf9\u65b9\u3002<\/li>\n<li>\u6b64\u65f6\u5ba2\u6237\u7aef\u56e0\u4e3a\u8fd8\u6ca1\u6709\u6536\u5230\u670d\u52a1\u7aef\u7684\u901a\u544a\u7a97\u53e3\u62a5\u6587\uff0c\u6240\u4ee5\u4e0d\u77e5\u9053\u6b64\u65f6\u63a5\u6536\u7a97\u53e3\u6536\u7f29\u6210\u4e86 100\uff0c\u5ba2\u6237\u7aef\u53ea\u4f1a\u770b\u81ea\u5df1\u7684\u53ef\u7528\u7a97\u53e3\u8fd8\u6709 220\uff0c\u6240\u4ee5\u5ba2\u6237\u7aef\u5c31\u53d1\u9001\u4e86 180 \u5b57\u8282\u6570\u636e\uff0c\u4e8e\u662f\u53ef\u7528\u7a97\u53e3\u51cf\u5c11\u5230 40\u3002<\/li>\n<li>\u670d\u52a1\u7aef\u6536\u5230\u4e86 180 \u5b57\u8282\u6570\u636e\u65f6\uff0c<strong>\u53d1\u73b0\u6570\u636e\u5927\u5c0f\u8d85\u8fc7\u4e86\u63a5\u6536\u7a97\u53e3\u7684\u5927\u5c0f\uff0c\u4e8e\u662f\u5c31\u628a\u6570\u636e\u5305\u4e22\u5931\u4e86\u3002<\/strong><\/li>\n<li>\u5ba2\u6237\u7aef\u6536\u5230\u7b2c 2 \u6b65\u65f6\uff0c\u670d\u52a1\u7aef\u53d1\u9001\u7684\u786e\u8ba4\u62a5\u6587\u548c\u901a\u544a\u7a97\u53e3\u62a5\u6587\uff0c\u5c1d\u8bd5\u51cf\u5c11\u53d1\u9001\u7a97\u53e3\u5230 100\uff0c\u628a\u7a97\u53e3\u7684\u53f3\u7aef\u5411\u5de6\u6536\u7f29\u4e86 80\uff0c\u6b64\u65f6\u53ef\u7528\u7a97\u53e3\u7684\u5927\u5c0f\u5c31\u4f1a\u51fa\u73b0\u8be1\u5f02\u7684\u8d1f\u503c\u3002<\/li>\n<\/ol>\n<p>\u6240\u4ee5\uff0c\u5982\u679c\u53d1\u751f\u4e86\u5148\u51cf\u5c11\u7f13\u5b58\uff0c\u518d\u6536\u7f29\u7a97\u53e3\uff0c\u5c31\u4f1a\u51fa\u73b0\u4e22\u5305\u7684\u73b0\u8c61\u3002<\/p>\n<p><strong>\u4e3a\u4e86\u9632\u6b62\u8fd9\u79cd\u60c5\u51b5\u53d1\u751f\uff0cTCP \u89c4\u5b9a\u662f\u4e0d\u5141\u8bb8\u540c\u65f6\u51cf\u5c11\u7f13\u5b58\u53c8\u6536\u7f29\u7a97\u53e3\u7684\uff0c\u800c\u662f\u91c7\u7528\u5148\u6536\u7f29\u7a97\u53e3\uff0c\u8fc7\u6bb5\u65f6\u95f4\u5728\u51cf\u5c11\u7f13\u5b58\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u907f\u514d\u4e86\u4e22\u5305\u60c5\u51b5\u3002<\/strong><\/p>\n<h4 id=\"h4-u7A97u53E3u5173u95ED\"><a class=\"reference-link\" name=\"\u7a97\u53e3\u5173\u95ed\"><\/a>\u7a97\u53e3\u5173\u95ed<\/h4>\n<p>\u5728\u524d\u9762\u6211\u4eec\u90fd\u770b\u5230\u4e86\uff0cTCP \u901a\u8fc7\u8ba9\u63a5\u6536\u65b9\u6307\u660e\u5e0c\u671b\u4ece\u53d1\u9001\u65b9\u63a5\u6536\u7684\u6570\u636e\u5927\u5c0f\uff08\u7a97\u53e3\u5927\u5c0f\uff09\u6765\u8fdb\u884c\u6d41\u91cf\u63a7\u5236\u3002<\/p>\n<p><strong>\u5982\u679c\u7a97\u53e3\u5927\u5c0f\u4e3a 0 \u65f6\uff0c\u5c31\u4f1a\u963b\u6b62\u53d1\u9001\u65b9\u7ed9\u63a5\u6536\u65b9\u4f20\u9012\u6570\u636e\uff0c\u76f4\u5230\u7a97\u53e3\u53d8\u4e3a\u975e 0 \u4e3a\u6b62\uff0c\u8fd9\u5c31\u662f\u7a97\u53e3\u5173\u95ed\u3002<\/strong><\/p>\n<blockquote><p>\u7a97\u53e3\u5173\u95ed\u6f5c\u5728\u7684\u5371\u9669<\/p><\/blockquote>\n<p>\u63a5\u6536\u65b9\u5411\u53d1\u9001\u65b9\u901a\u544a\u7a97\u53e3\u5927\u5c0f\u65f6\uff0c\u662f\u901a\u8fc7\u00a0<code>ACK<\/code>\u00a0\u62a5\u6587\u6765\u901a\u544a\u7684\u3002<\/p>\n<p>\u90a3\u4e48\uff0c\u5f53\u53d1\u751f\u7a97\u53e3\u5173\u95ed\u65f6\uff0c\u63a5\u6536\u65b9\u5904\u7406\u5b8c\u6570\u636e\u540e\uff0c\u4f1a\u5411\u53d1\u9001\u65b9\u901a\u544a\u4e00\u4e2a\u7a97\u53e3\u975e 0 \u7684 ACK \u62a5\u6587\uff0c\u5982\u679c\u8fd9\u4e2a\u901a\u544a\u7a97\u53e3\u7684 ACK \u62a5\u6587\u5728\u7f51\u7edc\u4e2d\u4e22\u5931\u4e86\uff0c\u90a3\u9ebb\u70e6\u5c31\u5927\u4e86\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/babdcf6c1574d8bf2638ec1d561941a7.png\" alt=\"5682e0345a01e700bc2080d0f103d83d.png\" \/><\/p>\n<p>\u8fd9\u4f1a\u5bfc\u81f4\u53d1\u9001\u65b9\u4e00\u76f4\u7b49\u5f85\u63a5\u6536\u65b9\u7684\u975e 0 \u7a97\u53e3\u901a\u77e5\uff0c\u63a5\u6536\u65b9\u4e5f\u4e00\u76f4\u7b49\u5f85\u53d1\u9001\u65b9\u7684\u6570\u636e\uff0c\u5982\u4e0d\u4e0d\u91c7\u53d6\u63aa\u65bd\uff0c\u8fd9\u79cd\u76f8\u4e92\u7b49\u5f85\u7684\u8fc7\u7a0b\uff0c\u4f1a\u9020\u6210\u4e86\u6b7b\u9501\u7684\u73b0\u8c61\u3002<\/p>\n<blockquote><p>TCP \u662f\u5982\u4f55\u89e3\u51b3\u7a97\u53e3\u5173\u95ed\u65f6\uff0c\u6f5c\u5728\u7684\u6b7b\u9501\u73b0\u8c61\u5462\uff1f<\/p><\/blockquote>\n<p>\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0cTCP \u4e3a\u6bcf\u4e2a\u8fde\u63a5\u8bbe\u6709\u4e00\u4e2a\u6301\u7eed\u5b9a\u65f6\u5668\uff0c<strong>\u53ea\u8981 TCP \u8fde\u63a5\u4e00\u65b9\u6536\u5230\u5bf9\u65b9\u7684\u96f6\u7a97\u53e3\u901a\u77e5\uff0c\u5c31\u542f\u52a8\u6301\u7eed\u8ba1\u65f6\u5668\u3002<\/strong><\/p>\n<p>\u5982\u679c\u6301\u7eed\u8ba1\u65f6\u5668\u8d85\u65f6\uff0c\u5c31\u4f1a\u53d1\u9001<strong>\u7a97\u53e3\u63a2\u6d4b ( Window<br \/>\nprobe ) \u62a5\u6587<\/strong>\uff0c\u800c\u5bf9\u65b9\u5728\u786e\u8ba4\u8fd9\u4e2a\u63a2\u6d4b\u62a5\u6587\u65f6\uff0c\u7ed9\u51fa\u81ea\u5df1\u73b0\u5728\u7684\u63a5\u6536\u7a97\u53e3\u5927\u5c0f\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/6a1d04e9f465c37bf1afd7cb103e2947.png\" alt=\"aa06ea2a100f495ab20f2dbea4678170.png\" \/><\/p>\n<ul>\n<li>\u5982\u679c\u63a5\u6536\u7a97\u53e3\u4ecd\u7136\u4e3a 0\uff0c\u90a3\u4e48\u6536\u5230\u8fd9\u4e2a\u62a5\u6587\u7684\u4e00\u65b9\u5c31\u4f1a\u91cd\u65b0\u542f\u52a8\u6301\u7eed\u8ba1\u65f6\u5668\uff1b<\/li>\n<li>\u5982\u679c\u63a5\u6536\u7a97\u53e3\u4e0d\u662f 0\uff0c\u90a3\u4e48\u6b7b\u9501\u7684\u5c40\u9762\u5c31\u53ef\u4ee5\u88ab\u6253\u7834\u4e86\u3002<\/li>\n<\/ul>\n<p>\u7a97\u53e3\u63a2\u67e5\u63a2\u6d4b\u7684\u6b21\u6570\u4e00\u822c\u4e3a 3 \u6b64\u6b21\uff0c\u6bcf\u6b21\u6b21\u5927\u7ea6 30-60 \u79d2\uff08\u4e0d\u540c\u7684\u5b9e\u73b0\u53ef\u80fd\u4f1a\u4e0d\u4e00\u6837\uff09\u3002\u5982\u679c 3 \u6b21\u8fc7\u540e\u63a5\u6536\u7a97\u53e3\u8fd8\u662f 0 \u7684\u8bdd\uff0c\u6709\u7684 TCP \u5b9e\u73b0\u5c31\u4f1a\u53d1\u00a0<code>RST<\/code>\u00a0\u62a5\u6587\u6765\u4e2d\u65ad\u8fde\u63a5\u3002<\/p>\n<h4 id=\"h4-u7CCAu6D82u7A97u53E3u7EFCu5408u75C7\"><a class=\"reference-link\" name=\"\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7\"><\/a>\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7<\/h4>\n<p>\u5982\u679c\u63a5\u6536\u65b9\u592a\u5fd9\u4e86\uff0c\u6765\u4e0d\u53ca\u53d6\u8d70\u63a5\u6536\u7a97\u53e3\u91cc\u7684\u6570\u636e\uff0c\u90a3\u4e48\u5c31\u4f1a\u5bfc\u81f4\u53d1\u9001\u65b9\u7684\u53d1\u9001\u7a97\u53e3\u8d8a\u6765\u8d8a\u5c0f\u3002<\/p>\n<p>\u5230\u6700\u540e\uff0c<strong>\u5982\u679c\u63a5\u6536\u65b9\u817e\u51fa\u51e0\u4e2a\u5b57\u8282\u5e76\u544a\u8bc9\u53d1\u9001\u65b9\u73b0\u5728\u6709\u51e0\u4e2a\u5b57\u8282\u7684\u7a97\u53e3\uff0c\u800c\u53d1\u9001\u65b9\u4f1a\u4e49\u65e0\u53cd\u987e\u5730\u53d1\u9001\u8fd9\u51e0\u4e2a\u5b57\u8282\uff0c\u8fd9\u5c31\u662f\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7<\/strong>\u3002<\/p>\n<p>\u8981\u77e5\u9053\uff0c\u6211\u4eec\u7684\u00a0<code>TCP + IP<\/code>\u00a0\u5934\u6709\u00a0<code>40<\/code>\u00a0\u4e2a\u5b57\u8282\uff0c\u4e3a\u4e86\u4f20\u8f93\u90a3\u51e0\u4e2a\u5b57\u8282\u7684\u6570\u636e\uff0c\u8981\u8fbe\u4e0a\u8fd9\u4e48\u5927\u7684\u5f00\u9500\uff0c\u8fd9\u592a\u4e0d\u7ecf\u6d4e\u4e86\u3002<\/p>\n<p>\u5c31\u597d\u50cf\u4e00\u4e2a\u53ef\u4ee5\u627f\u8f7d 50 \u4eba\u7684\u5927\u5df4\u8f66\uff0c\u6bcf\u6b21\u6765\u4e86\u4e00\u4e24\u4e2a\u4eba\uff0c\u5c31\u76f4\u63a5\u53d1\u8f66\u3002\u9664\u975e\u5bb6\u91cc\u6709\u77ff\u7684\u5927\u5df4\u53f8\u673a\uff0c\u624d\u6562\u8fd9\u6837\u73a9\uff0c\u4e0d\u7136\u8fdf\u65e9\u7834\u4ea7\u3002\u8981\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u4e5f\u4e0d\u96be\uff0c\u5927\u5df4\u53f8\u673a\u7b49\u4e58\u5ba2\u6570\u91cf\u8d85\u8fc7\u4e86 25 \u4e2a\uff0c\u624d\u8ba4\u5b9a\u53ef\u4ee5\u53d1\u8f66\u3002<\/p>\n<p>\u73b0\u4e3e\u4e2a\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7\u7684\u6817\u5b50\uff0c\u8003\u8651\u4ee5\u4e0b\u573a\u666f\uff1a<\/p>\n<p>\u63a5\u6536\u65b9\u7684\u7a97\u53e3\u5927\u5c0f\u662f 360 \u5b57\u8282\uff0c\u4f46\u63a5\u6536\u65b9\u7531\u4e8e\u67d0\u4e9b\u539f\u56e0\u9677\u5165\u56f0\u5883\uff0c\u5047\u8bbe\u63a5\u6536\u65b9\u7684\u5e94\u7528\u5c42\u8bfb\u53d6\u7684\u80fd\u529b\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>\u63a5\u6536\u65b9\u6bcf\u63a5\u6536 3 \u4e2a\u5b57\u8282\uff0c\u5e94\u7528\u7a0b\u5e8f\u5c31\u53ea\u80fd\u4ece\u7f13\u51b2\u533a\u4e2d\u8bfb\u53d6 1 \u4e2a\u5b57\u8282\u7684\u6570\u636e\uff1b<\/li>\n<li>\u5728\u4e0b\u4e00\u4e2a\u53d1\u9001\u65b9\u7684 TCP \u6bb5\u5230\u8fbe\u4e4b\u524d\uff0c\u5e94\u7528\u7a0b\u5e8f<br \/>\n\u8fd8\u4ece\u7f13\u51b2\u533a\u4e2d\u8bfb\u53d6\u4e86 40 \u4e2a\u989d\u5916\u7684\u5b57\u8282\uff1b<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/15b0670998ad4746ba21f704c142e392.png\" alt=\"03084d5d2c687a03df0327513120daef.png\" \/><\/p>\n<p>\u6bcf\u4e2a\u8fc7\u7a0b\u7684\u7a97\u53e3\u5927\u5c0f\u7684\u53d8\u5316\uff0c\u5728\u56fe\u4e2d\u90fd\u63cf\u8ff0\u7684\u5f88\u6e05\u695a\u4e86\uff0c\u53ef\u4ee5\u53d1\u73b0\u7a97\u53e3\u4e0d\u65ad\u51cf\u5c11\u4e86\uff0c\u5e76\u4e14\u53d1\u9001\u7684\u6570\u636e\u90fd\u662f\u6bd4\u8f83\u5c0f\u7684\u4e86\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7\u7684\u73b0\u8c61\u662f\u53ef\u4ee5\u53d1\u751f\u5728\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\uff1a<\/p>\n<ul>\n<li>\u63a5\u6536\u65b9\u53ef\u4ee5\u901a\u544a\u4e00\u4e2a\u5c0f\u7684\u7a97\u53e3<\/li>\n<li>\u800c\u53d1\u9001\u65b9\u53ef\u4ee5\u53d1\u9001\u5c0f\u6570\u636e<\/li>\n<\/ul>\n<p>\u4e8e\u662f\uff0c\u8981\u89e3\u51b3\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u75c7\uff0c\u5c31\u89e3\u51b3\u4e0a\u9762\u4e24\u4e2a\u95ee\u9898\u5c31\u53ef\u4ee5\u4e86<\/p>\n<ul>\n<li>\u8ba9\u63a5\u6536\u65b9\u4e0d\u901a\u544a\u5c0f\u7a97\u53e3\u7ed9\u53d1\u9001\u65b9<\/li>\n<li>\u8ba9\u53d1\u9001\u65b9\u907f\u514d\u53d1\u9001\u5c0f\u6570\u636e<\/li>\n<\/ul>\n<blockquote><p>\u600e\u4e48\u8ba9\u63a5\u6536\u65b9\u4e0d\u901a\u544a\u5c0f\u7a97\u53e3\u5462\uff1f<\/p><\/blockquote>\n<p>\u63a5\u6536\u65b9\u901a\u5e38\u7684\u7b56\u7565\u5982\u4e0b:<\/p>\n<p>\u5f53\u300c\u7a97\u53e3\u5927\u5c0f\u300d\u5c0f\u4e8e min( MSS\uff0c\u7f13\u5b58\u7a7a\u95f4\/2 ) \uff0c\u4e5f\u5c31\u662f\u5c0f\u4e8e MSS \u4e0e 1\/2 \u7f13\u5b58\u5927\u5c0f\u4e2d\u7684\u6700\u5c0f\u503c\u65f6\uff0c\u5c31\u4f1a\u5411\u53d1\u9001\u65b9\u901a\u544a\u7a97\u53e3\u4e3a\u00a0<code>0<\/code>\uff0c\u4e5f\u5c31\u963b\u6b62\u4e86\u53d1\u9001\u65b9\u518d\u53d1\u6570\u636e\u8fc7\u6765\u3002<\/p>\n<p>\u7b49\u5230\u63a5\u6536\u65b9\u5904\u7406\u4e86\u4e00\u4e9b\u6570\u636e\u540e\uff0c\u7a97\u53e3\u5927\u5c0f &gt;= MSS\uff0c\u6216\u8005\u63a5\u6536\u65b9\u7f13\u5b58\u7a7a\u95f4\u6709\u4e00\u534a\u53ef\u4ee5\u4f7f\u7528\uff0c\u5c31\u53ef\u4ee5\u628a\u7a97\u53e3\u6253\u5f00\u8ba9\u53d1\u9001\u65b9\u53d1\u9001\u6570\u636e\u8fc7\u6765\u3002<\/p>\n<blockquote><p>\u600e\u4e48\u8ba9\u53d1\u9001\u65b9\u907f\u514d\u53d1\u9001\u5c0f\u6570\u636e\u5462\uff1f<\/p><\/blockquote>\n<p>\u53d1\u9001\u65b9\u901a\u5e38\u7684\u7b56\u7565:<\/p>\n<p>\u4f7f\u7528 Nagle \u7b97\u6cd5\uff0c\u8be5\u7b97\u6cd5\u7684\u601d\u8def\u662f\u5ef6\u65f6\u5904\u7406\uff0c\u5b83\u6ee1\u8db3\u4ee5\u4e0b\u4e24\u4e2a\u6761\u4ef6\u4e2d\u7684\u4e00\u6761\u624d\u53ef\u4ee5\u53d1\u9001\u6570\u636e\uff1a<\/p>\n<ul>\n<li>\u8981\u7b49\u5230\u7a97\u53e3\u5927\u5c0f &gt;=\u00a0<code>MSS<\/code>\u00a0\u6216\u662f \u6570\u636e\u5927\u5c0f &gt;=\u00a0<code>MSS<\/code><\/li>\n<li>\u6536\u5230\u4e4b\u524d\u53d1\u9001\u6570\u636e\u7684\u00a0<code>ack<\/code>\u00a0\u56de\u5305<\/li>\n<\/ul>\n<p>\u53ea\u8981\u6ca1\u6ee1\u8db3\u4e0a\u9762\u6761\u4ef6\u4e2d\u7684\u4e00\u6761\uff0c\u53d1\u9001\u65b9\u4e00\u76f4\u5728\u56e4\u79ef\u6570\u636e\uff0c\u76f4\u5230\u6ee1\u8db3\u4e0a\u9762\u7684\u53d1\u9001\u6761\u4ef6\u3002<\/p>\n<p>\u53e6\u5916\uff0cNagle \u7b97\u6cd5\u9ed8\u8ba4\u662f\u6253\u5f00\u7684\uff0c\u5982\u679c\u5bf9\u4e8e\u4e00\u4e9b\u9700\u8981\u5c0f\u6570\u636e\u5305\u4ea4\u4e92\u7684\u573a\u666f\u7684\u7a0b\u5e8f\uff0c\u6bd4\u5982\uff0ctelnet \u6216 ssh \u8fd9\u6837\u7684\u4ea4\u4e92\u6027\u6bd4\u8f83\u5f3a\u7684\u7a0b\u5e8f\uff0c\u5219\u9700\u8981\u5173\u95ed Nagle \u7b97\u6cd5\u3002<\/p>\n<h1 id=\"h1-tcp-\"><a class=\"reference-link\" name=\"TCP \u62e5\u585e\u63a7\u5236\"><\/a>TCP \u62e5\u585e\u63a7\u5236<\/h1>\n<blockquote><p>\u4e3a\u4ec0\u4e48\u8981\u6709\u62e5\u585e\u63a7\u5236\u5440\uff0c\u4e0d\u662f\u6709\u6d41\u91cf\u63a7\u5236\u4e86\u5417\uff1f<\/p><\/blockquote>\n<p>\u524d\u9762\u7684\u6d41\u91cf\u63a7\u5236\u662f\u907f\u514d\u300c\u53d1\u9001\u65b9\u300d\u7684\u6570\u636e\u586b\u6ee1\u300c\u63a5\u6536\u65b9\u300d\u7684\u7f13\u5b58\uff0c\u4f46\u662f\u5e76\u4e0d\u77e5\u9053\u7f51\u7edc\u7684\u4e2d\u53d1\u751f\u4e86\u4ec0\u4e48\u3002<\/p>\n<p>\u4e00\u822c\u6765\u8bf4\uff0c\u8ba1\u7b97\u673a\u7f51\u7edc\u90fd\u5904\u5728\u4e00\u4e2a\u5171\u4eab\u7684\u73af\u5883\u3002\u56e0\u6b64\u4e5f\u6709\u53ef\u80fd\u4f1a\u56e0\u4e3a\u5176\u4ed6\u4e3b\u673a\u4e4b\u95f4\u7684\u901a\u4fe1\u4f7f\u5f97\u7f51\u7edc\u62e5\u5835\u3002<\/p>\n<p><strong>\u5728\u7f51\u7edc\u51fa\u73b0\u62e5\u5835\u65f6\uff0c\u5982\u679c\u7ee7\u7eed\u53d1\u9001\u5927\u91cf\u6570\u636e\u5305\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u6570\u636e\u5305\u65f6\u5ef6\u3001\u4e22\u5931\u7b49\uff0c\u8fd9\u65f6 TCP \u5c31\u4f1a\u91cd\u4f20\u6570\u636e\uff0c\u4f46\u662f\u4e00\u91cd\u4f20\u5c31\u4f1a\u5bfc\u81f4\u7f51\u7edc\u7684\u8d1f\u62c5\u66f4\u91cd\uff0c\u4e8e\u662f\u4f1a\u5bfc\u81f4\u66f4\u5927\u7684\u5ef6\u8fdf\u4ee5\u53ca\u66f4\u591a\u7684\u4e22\u5305\uff0c\u8fd9\u4e2a\u60c5\u51b5\u5c31\u4f1a\u8fdb\u5165\u6076\u6027\u5faa\u73af\u88ab\u4e0d\u65ad\u5730\u653e\u5927\u2026<\/strong><\/p>\n<p>\u6240\u4ee5\uff0cTCP \u4e0d\u80fd\u5ffd\u7565\u7f51\u7edc\u4e0a\u53d1\u751f\u7684\u4e8b\uff0c\u5b83\u88ab\u8bbe\u8ba1\u6210\u4e00\u4e2a\u65e0\u79c1\u7684\u534f\u8bae\uff0c\u5f53\u7f51\u7edc\u53d1\u9001\u62e5\u585e\u65f6\uff0cTCP \u4f1a\u81ea\u6211\u727a\u7272\uff0c\u964d\u4f4e\u53d1\u9001\u7684\u6570\u636e\u91cf\u3002<\/p>\n<p>\u4e8e\u662f\uff0c\u5c31\u6709\u4e86<strong>\u62e5\u585e\u63a7\u5236<\/strong>\uff0c\u63a7\u5236\u7684\u76ee\u7684\u5c31\u662f<strong>\u907f\u514d\u300c\u53d1\u9001\u65b9\u300d\u7684\u6570\u636e\u586b\u6ee1\u6574\u4e2a\u7f51\u7edc\u3002<\/strong><\/p>\n<p>\u4e3a\u4e86\u5728\u300c\u53d1\u9001\u65b9\u300d\u8c03\u8282\u6240\u8981\u53d1\u9001\u6570\u636e\u7684\u91cf\uff0c\u5b9a\u4e49\u4e86\u4e00\u4e2a\u53eb\u505a\u300c<strong>\u62e5\u585e\u7a97\u53e3<\/strong>\u300d\u7684\u6982\u5ff5\u3002<\/p>\n<blockquote><p>\u4ec0\u4e48\u662f\u62e5\u585e\u7a97\u53e3\uff1f\u548c\u53d1\u9001\u7a97\u53e3\u6709\u4ec0\u4e48\u5173\u7cfb\u5462\uff1f<\/p><\/blockquote>\n<p><strong>\u62e5\u585e\u7a97\u53e3 cwnd<\/strong>\u662f\u53d1\u9001\u65b9\u7ef4\u62a4\u7684\u4e00\u4e2a \u7684\u72b6\u6001\u53d8\u91cf\uff0c\u5b83\u4f1a\u6839\u636e<strong>\u7f51\u7edc\u7684\u62e5\u585e\u7a0b\u5ea6\u52a8\u6001\u53d8\u5316\u7684<\/strong>\u3002<\/p>\n<p>\u6211\u4eec\u5728\u524d\u9762\u63d0\u5230\u8fc7\u53d1\u9001\u7a97\u53e3\u00a0<code>swnd<\/code>\u00a0\u548c\u63a5\u6536\u7a97\u53e3\u00a0<code>rwnd<\/code>\u00a0\u662f\u7ea6\u7b49\u4e8e\u7684\u5173\u7cfb\uff0c\u90a3\u4e48\u7531\u4e8e\u5165\u4e86\u62e5\u585e\u7a97\u53e3\u7684\u6982\u5ff5\u540e\uff0c\u6b64\u65f6\u53d1\u9001\u7a97\u53e3\u7684\u503c\u662fswnd = min(cwnd, rwnd)\uff0c\u4e5f\u5c31\u662f\u62e5\u585e\u7a97\u53e3\u548c\u63a5\u6536\u7a97\u53e3\u4e2d\u7684\u6700\u5c0f\u503c\u3002<\/p>\n<p>\u62e5\u585e\u7a97\u53e3\u00a0<code>cwnd<\/code>\u00a0\u53d8\u5316\u7684\u89c4\u5219\uff1a<\/p>\n<ul>\n<li>\u53ea\u8981\u7f51\u7edc\u4e2d\u6ca1\u6709\u51fa\u73b0\u62e5\u585e\uff0c<code>cwnd<\/code>\u00a0\u5c31\u4f1a\u589e\u5927\uff1b<\/li>\n<li>\u4f46\u7f51\u7edc\u4e2d\u51fa\u73b0\u4e86\u62e5\u585e\uff0c<code>cwnd<\/code>\u00a0\u5c31\u51cf\u5c11\uff1b<\/li>\n<\/ul>\n<blockquote><p>\u90a3\u4e48\u600e\u4e48\u77e5\u9053\u5f53\u524d\u7f51\u7edc\u662f\u5426\u51fa\u73b0\u4e86\u62e5\u585e\u5462\uff1f<\/p><\/blockquote>\n<p>\u5176\u5b9e\u53ea\u8981\u300c\u53d1\u9001\u65b9\u300d\u6ca1\u6709\u5728\u89c4\u5b9a\u65f6\u95f4\u5185\u63a5\u6536\u5230 ACK \u5e94\u7b54\u62a5\u6587\uff0c\u4e5f\u5c31\u662f<strong>\u53d1\u751f\u4e86\u8d85\u65f6\u91cd\u4f20\uff0c\u5c31\u4f1a\u8ba4\u4e3a\u7f51\u7edc\u51fa\u73b0\u4e86\u7528\u62e5\u585e\u3002<\/strong><\/p>\n<blockquote><p>\u62e5\u585e\u63a7\u5236\u6709\u54ea\u4e9b\u63a7\u5236\u7b97\u6cd5\uff1f<\/p><\/blockquote>\n<p>\u62e5\u585e\u63a7\u5236\u4e3b\u8981\u662f\u56db\u4e2a\u7b97\u6cd5\uff1a<\/p>\n<ul>\n<li>\u6162\u542f\u52a8<\/li>\n<li>\u62e5\u585e\u907f\u514d<\/li>\n<li>\u62e5\u585e\u53d1\u751f<\/li>\n<li>\u5feb\u901f\u6062\u590d<\/li>\n<\/ul>\n<h2 id=\"h2-u6162u542Fu52A8\"><a class=\"reference-link\" name=\"\u6162\u542f\u52a8\"><\/a>\u6162\u542f\u52a8<\/h2>\n<p>TCP \u5728\u521a\u5efa\u7acb\u8fde\u63a5\u5b8c\u6210\u540e\uff0c\u9996\u5148\u662f\u6709\u4e2a\u6162\u542f\u52a8\u7684\u8fc7\u7a0b\uff0c\u8fd9\u4e2a\u6162\u542f\u52a8\u7684\u610f\u601d\u5c31\u662f\u4e00\u70b9\u4e00\u70b9\u7684\u63d0\u9ad8\u53d1\u9001\u6570\u636e\u5305\u7684\u6570\u91cf\uff0c\u5982\u679c\u4e00\u4e0a\u6765\u5c31\u53d1\u5927\u91cf\u7684\u6570\u636e\uff0c\u8fd9\u4e0d\u662f\u7ed9\u7f51\u7edc\u6dfb\u5835\u5417\uff1f<\/p>\n<p>\u6162\u542f\u52a8\u7684\u7b97\u6cd5\u8bb0\u4f4f\u4e00\u4e2a\u89c4\u5219\u5c31\u884c\uff1a<strong>\u5f53\u53d1\u9001\u65b9\u6bcf\u6536\u5230\u4e00\u4e2a ACK\uff0c\u5c31\u62e5\u585e\u7a97\u53e3 cwnd \u7684\u5927\u5c0f\u5c31\u4f1a\u52a0 1\u3002<\/strong><\/p>\n<p>\u8fd9\u91cc\u5047\u5b9a\u62e5\u585e\u7a97\u53e3\u00a0<code>cwnd<\/code>\u00a0\u548c\u53d1\u9001\u7a97\u53e3\u00a0<code>swnd<\/code>\u00a0\u76f8\u7b49\uff0c\u4e0b\u9762\u4e3e\u4e2a\u6817\u5b50\uff1a<\/p>\n<ul>\n<li>\u8fde\u63a5\u5efa\u7acb\u5b8c\u6210\u540e\uff0c\u4e00\u5f00\u59cb\u521d\u59cb\u5316\u00a0<code>cwnd = 1<\/code>\uff0c\u8868\u793a\u53ef\u4ee5\u4f20\u4e00\u4e2a\u00a0<code>MSS<\/code>\u00a0\u5927\u5c0f\u7684\u6570\u636e\u3002<\/li>\n<li>\u5f53\u6536\u5230\u4e00\u4e2a ACK \u786e\u8ba4\u5e94\u7b54\u540e\uff0ccwnd \u589e\u52a0 1\uff0c\u4e8e\u662f\u4e00\u6b21\u80fd\u591f\u53d1\u9001 2 \u4e2a<\/li>\n<li>\u5f53\u6536\u5230 2 \u4e2a\u7684 ACK \u786e\u8ba4\u5e94\u7b54\u540e\uff0c cwnd \u589e\u52a0 2\uff0c\u4e8e\u662f\u5c31\u53ef\u4ee5\u6bd4\u4e4b\u524d\u591a\u53d12 \u4e2a\uff0c\u6240\u4ee5\u8fd9\u4e00\u6b21\u80fd\u591f\u53d1\u9001 4 \u4e2a<\/li>\n<li>\u5f53\u8fd9 4 \u4e2a\u7684 ACK \u786e\u8ba4\u5230\u6765\u7684\u65f6\u5019\uff0c\u6bcf\u4e2a\u786e\u8ba4 cwnd \u589e\u52a0 1\uff0c 4 \u4e2a\u786e\u8ba4 cwnd \u589e\u52a0 4\uff0c\u4e8e\u662f\u5c31\u53ef\u4ee5\u6bd4\u4e4b\u524d\u591a\u53d1 4 \u4e2a\uff0c\u6240\u4ee5\u8fd9\u4e00\u6b21\u80fd\u591f\u53d1\u9001 8 \u4e2a\u3002<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/cceac32203384825e68438b7763e6c2d.png\" alt=\"b26d1e21c8959cad24be46d2edb7677c.png\" \/><\/p>\n<p>\u53ef\u4ee5\u770b\u51fa\u6162\u542f\u52a8\u7b97\u6cd5\uff0c\u53d1\u5305\u7684\u4e2a\u6570\u662f<strong>\u6307\u6570\u6027\u7684\u589e\u957f<\/strong>\u3002<\/p>\n<blockquote><p>\u90a3\u6162\u542f\u52a8\u6da8\u5230\u4ec0\u4e48\u65f6\u5019\u662f\u4e2a\u5934\u5462\uff1f<\/p><\/blockquote>\n<p>\u6709\u4e00\u4e2a\u53eb\u6162\u542f\u52a8\u95e8\u9650\u00a0<code>ssthresh<\/code>\u00a0\uff08slow start threshold\uff09\u72b6\u6001\u53d8\u91cf\u3002<\/p>\n<ul>\n<li>\u5f53\u00a0<code>cwnd<\/code>\u00a0&lt;\u00a0<code>ssthresh<\/code>\u00a0\u65f6\uff0c\u4f7f\u7528\u6162\u542f\u52a8\u7b97\u6cd5\u3002<\/li>\n<li>\u5f53\u00a0<code>cwnd<\/code>\u00a0&gt;=\u00a0<code>ssthresh<\/code>\u00a0\u65f6\uff0c\u5c31\u4f1a\u4f7f\u7528\u300c\u62e5\u585e\u907f\u514d\u7b97\u6cd5\u300d\u3002<\/li>\n<\/ul>\n<h2 id=\"h2-u62E5u585Eu907Fu514Du7B97u6CD5\"><a class=\"reference-link\" name=\"\u62e5\u585e\u907f\u514d\u7b97\u6cd5\"><\/a>\u62e5\u585e\u907f\u514d\u7b97\u6cd5<\/h2>\n<p>\u524d\u9762\u8bf4\u9053\uff0c\u5f53\u62e5\u585e\u7a97\u53e3\u00a0<code>cwnd<\/code>\u00a0\u300c\u8d85\u8fc7\u300d\u6162\u542f\u52a8\u95e8\u9650\u00a0<code>ssthresh<\/code>\u00a0\u5c31\u4f1a\u8fdb\u5165\u62e5\u585e\u907f\u514d\u7b97\u6cd5\u3002<\/p>\n<p>\u4e00\u822c\u6765\u8bf4\u00a0<code>ssthresh<\/code>\u00a0\u7684\u5927\u5c0f\u662f\u00a0<code>65535<\/code>\u00a0\u5b57\u8282\u3002<\/p>\n<p>\u90a3\u4e48\u8fdb\u5165\u62e5\u585e\u907f\u514d\u7b97\u6cd5\u540e\uff0c\u5b83\u7684\u89c4\u5219\u662f\uff1a<strong>\u6bcf\u5f53\u6536\u5230\u4e00\u4e2a ACK \u65f6\uff0ccwnd \u589e\u52a0 1\/cwnd\u3002<\/strong><\/p>\n<p>\u63a5\u4e0a\u524d\u9762\u7684\u6162\u542f\u52a8\u7684\u6817\u5b50\uff0c\u73b0\u5047\u5b9a\u00a0<code>ssthresh<\/code>\u00a0\u4e3a\u00a0<code>8<\/code>\uff1a<\/p>\n<ul>\n<li>\u5f53 8 \u4e2a ACK \u5e94\u7b54\u786e\u8ba4\u5230\u6765\u65f6\uff0c\u6bcf\u4e2a\u786e\u8ba4\u589e\u52a0 1\/8\uff0c8 \u4e2a ACK \u786e\u8ba4 cwnd \u4e00\u5171\u589e\u52a0 1\uff0c\u4e8e\u662f\u8fd9\u4e00\u6b21\u80fd\u591f\u53d1\u9001 9 \u4e2a\u00a0<code>MSS<\/code>\u00a0\u5927\u5c0f\u7684\u6570\u636e\uff0c\u53d8\u6210\u4e86<strong>\u7ebf\u6027\u589e\u957f\u3002<\/strong><\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/39d396110f081622c40b2332cce3d5d9.png\" alt=\"ee7eaccc74d83da2f3147eb5fd12b1f9.png\" \/><\/p>\n<p>\u6240\u4ee5\uff0c\u6211\u4eec\u53ef\u4ee5\u53d1\u73b0\uff0c\u62e5\u585e\u907f\u514d\u7b97\u6cd5\u5c31\u662f\u5c06\u539f\u672c\u6162\u542f\u52a8\u7b97\u6cd5\u7684\u6307\u6570\u589e\u957f\u53d8\u6210\u4e86\u7ebf\u6027\u589e\u957f\uff0c\u8fd8\u662f\u589e\u957f\u9636\u6bb5\uff0c\u4f46\u662f\u589e\u957f\u901f\u5ea6\u7f13\u6162\u4e86\u4e00\u4e9b\u3002<\/p>\n<p>\u5c31\u8fd9\u4e48\u4e00\u76f4\u589e\u957f\u7740\u540e\uff0c\u7f51\u7edc\u5c31\u4f1a\u6162\u6162\u8fdb\u5165\u4e86\u62e5\u585e\u7684\u72b6\u51b5\u4e86\uff0c\u4e8e\u662f\u5c31\u4f1a\u51fa\u73b0\u4e22\u5305\u73b0\u8c61\uff0c\u8fd9\u65f6\u5c31\u9700\u8981\u5bf9\u4e22\u5931\u7684\u6570\u636e\u5305\u8fdb\u884c\u91cd\u4f20\u3002<\/p>\n<p>\u5f53\u89e6\u53d1\u4e86\u91cd\u4f20\u673a\u5236\uff0c\u4e5f\u5c31\u8fdb\u5165\u4e86\u300c\u62e5\u585e\u53d1\u751f\u7b97\u6cd5\u300d\u3002<\/p>\n<h2 id=\"h2-u62E5u585Eu53D1u751F\"><a class=\"reference-link\" name=\"\u62e5\u585e\u53d1\u751f\"><\/a>\u62e5\u585e\u53d1\u751f<\/h2>\n<p>\u5f53\u7f51\u7edc\u51fa\u73b0\u62e5\u585e\uff0c\u4e5f\u5c31\u662f\u4f1a\u53d1\u751f\u6570\u636e\u5305\u91cd\u4f20\uff0c\u91cd\u4f20\u673a\u5236\u4e3b\u8981\u6709\u4e24\u79cd\uff1a<\/p>\n<ul>\n<li>\u8d85\u65f6\u91cd\u4f20<\/li>\n<li>\u5feb\u901f\u91cd\u4f20<\/li>\n<\/ul>\n<p>\u8fd9\u4e24\u79cd\u4f7f\u7528\u7684\u62e5\u585e\u53d1\u9001\u7b97\u6cd5\u662f\u4e0d\u540c\u7684\uff0c\u63a5\u4e0b\u6765\u5206\u522b\u6765\u8bf4\u8bf4\u3002<\/p>\n<h3 id=\"h3-u53D1u751Fu8D85u65F6u91CDu4F20u7684u62E5u585Eu53D1u751Fu7B97u6CD5\"><a class=\"reference-link\" name=\"\u53d1\u751f\u8d85\u65f6\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f\u7b97\u6cd5\"><\/a>\u53d1\u751f\u8d85\u65f6\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f\u7b97\u6cd5<\/h3>\n<p>\u5f53\u53d1\u751f\u4e86\u300c\u8d85\u65f6\u91cd\u4f20\u300d\uff0c\u5219\u5c31\u4f1a\u4f7f\u7528\u62e5\u585e\u53d1\u751f\u7b97\u6cd5\u3002<\/p>\n<p>\u8fd9\u4e2a\u65f6\u5019\uff0csshresh \u548c cwnd \u7684\u503c\u4f1a\u53d1\u751f\u53d8\u5316\uff1a<\/p>\n<ul>\n<li><code>ssthresh<\/code>\u00a0\u8bbe\u4e3a\u00a0<code>cwnd\/2<\/code>\uff0c<\/li>\n<li><code>cwnd<\/code>\u00a0\u91cd\u7f6e\u4e3a\u00a0<code>1<\/code><\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"\/wp-content\/uploads\/replace\/2f6eb70cff518b93f3d7ed4b5c2f7b43.png\" alt=\"56383fe8de823aa5976e1ed09635c291.png\" \/><\/p>\n<p>\u63a5\u7740\uff0c\u5c31\u91cd\u65b0\u5f00\u59cb\u6162\u542f\u52a8\uff0c\u6162\u542f\u52a8\u662f\u4f1a\u7a81\u7136\u51cf\u5c11\u6570\u636e\u6d41\u7684\u3002\u8fd9\u771f\u662f\u4e00\u65e6\u300c\u8d85\u65f6\u91cd\u4f20\u300d\uff0c\u9a6c\u4e0a\u56de\u5230\u89e3\u653e\u524d\u3002\u4f46\u662f\u8fd9\u79cd\u65b9\u5f0f\u592a\u6fc0\u8fdb\u4e86\uff0c\u53cd\u5e94\u4e5f\u5f88\u5f3a\u70c8\uff0c\u4f1a\u9020\u6210\u7f51\u7edc\u5361\u987f\u3002<\/p>\n<p>\u5c31\u597d\u50cf\u672c\u6765\u5728\u79cb\u540d\u5c71\u9ad8\u901f\u6f02\u79fb\u7740\uff0c\u7a81\u7136\u6765\u4e2a\u7d27\u6025\u5239\u8f66\uff0c\u8f6e\u80ce\u53d7\u5f97\u4e86\u5417\u3002\u3002\u3002<\/p>\n<h3 id=\"h3-u53D1u751Fu5FEBu901Fu91CDu4F20u7684u62E5u585Eu53D1u751Fu7B97u6CD5\"><a class=\"reference-link\" name=\"\u53d1\u751f\u5feb\u901f\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f\u7b97\u6cd5\"><\/a>\u53d1\u751f\u5feb\u901f\u91cd\u4f20\u7684\u62e5\u585e\u53d1\u751f\u7b97\u6cd5<\/h3>\n<p>\u8fd8\u6709\u66f4\u597d\u7684\u65b9\u5f0f\uff0c\u524d\u9762\u6211\u4eec\u8bb2\u8fc7\u300c\u5feb\u901f\u91cd\u4f20\u7b97\u6cd5\u300d\u3002\u5f53\u63a5\u6536\u65b9\u53d1\u73b0\u4e22\u4e86\u4e00\u4e2a\u4e2d\u95f4\u5305\u7684\u65f6\u5019\uff0c\u53d1\u9001\u4e09\u6b21\u524d\u4e00\u4e2a\u5305\u7684 ACK\uff0c\u4e8e\u662f\u53d1\u9001\u7aef\u5c31\u4f1a\u5feb\u901f\u5730\u91cd\u4f20\uff0c\u4e0d\u5fc5\u7b49\u5f85\u8d85\u65f6\u518d\u91cd\u4f20\u3002<\/p>\n<p>TCP \u8ba4\u4e3a\u8fd9\u79cd\u60c5\u51b5\u4e0d\u4e25\u91cd\uff0c\u56e0\u4e3a\u5927\u90e8\u5206\u6ca1\u4e22\uff0c\u53ea\u4e22\u4e86\u4e00\u5c0f\u90e8\u5206\uff0c\u5219\u00a0<code>ssthresh<\/code>\u00a0\u548c\u00a0<code>cwnd<\/code>\u00a0\u53d8\u5316\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li><code>cwnd = cwnd\/2<\/code>\u00a0\uff0c\u4e5f\u5c31\u662f\u8bbe\u7f6e\u4e3a\u539f\u6765\u7684\u4e00\u534a;<\/li>\n<li><code>ssthresh = cwnd<\/code>;<\/li>\n<li>\u8fdb\u5165\u5feb\u901f\u6062\u590d\u7b97\u6cd5<\/li>\n<\/ul>\n<h2 id=\"h2-u5FEBu901Fu6062u590D\"><a class=\"reference-link\" name=\"\u5feb\u901f\u6062\u590d\"><\/a>\u5feb\u901f\u6062\u590d<\/h2>\n<p>\u5feb\u901f\u91cd\u4f20\u548c\u5feb\u901f\u6062\u590d\u7b97\u6cd5\u4e00\u822c\u540c\u65f6\u4f7f\u7528\uff0c\u5feb\u901f\u6062\u590d\u7b97\u6cd5\u662f\u8ba4\u4e3a\uff0c\u4f60\u8fd8\u80fd\u6536\u5230 3 \u4e2a\u91cd\u590d ACK \u8bf4\u660e\u7f51\u7edc\u4e5f\u4e0d\u90a3\u4e48\u7cdf\u7cd5\uff0c\u6240\u4ee5\u6ca1\u6709\u5fc5\u8981\u50cf\u00a0<code>RTO<\/code>\u00a0\u8d85\u65f6\u90a3\u4e48\u5f3a\u70c8\u3002<\/p>\n<p>\u6b63\u5982\u524d\u9762\u6240\u8bf4\uff0c\u8fdb\u5165\u5feb\u901f\u6062\u590d\u4e4b\u524d\uff0c<code>cwnd<\/code>\u00a0\u548c\u00a0<code>ssthresh<\/code>\u00a0\u5df2\u88ab\u66f4\u65b0\u4e86\uff1a<\/p>\n<ul>\n<li><code>cwnd = cwnd\/2<\/code>\u00a0\uff0c\u4e5f\u5c31\u662f\u8bbe\u7f6e\u4e3a\u539f\u6765\u7684\u4e00\u534a;<\/li>\n<li><code>ssthresh = cwnd<\/code>;<\/li>\n<\/ul>\n<p>\u7136\u540e\uff0c\u8fdb\u5165\u5feb\u901f\u6062\u590d\u7b97\u6cd5\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>\u62e5\u585e\u7a97\u53e3\u00a0<code>cwnd = ssthresh + 3<\/code>\u00a0\uff08 3 \u7684\u610f\u601d\u662f\u786e\u8ba4\u6709 3 \u4e2a\u6570\u636e\u5305\u88ab\u6536\u5230\u4e86\uff09<\/li>\n<li>\u91cd\u4f20\u4e22\u5931\u7684\u6570\u636e\u5305<\/li>\n<li>\u5982\u679c\u518d\u6536\u5230\u91cd\u590d\u7684 ACK\uff0c\u90a3\u4e48 cwnd \u589e\u52a0 1<\/li>\n<li>\u5982\u679c\u6536\u5230\u65b0\u6570\u636e\u7684 ACK \u540e\uff0c\u8bbe\u7f6e cwnd \u4e3a ssthresh\uff0c\u63a5\u7740\u5c31\u8fdb\u5165\u4e86\u62e5\u585e\u907f\u514d\u7b97\u6cd5<\/li>\n<\/ul>\n<p>\u4e5f\u5c31\u662f\u6ca1\u6709\u50cf\u300c\u8d85\u65f6\u91cd\u4f20\u300d\u4e00\u591c\u56de\u5230\u89e3\u653e\u524d\uff0c\u800c\u662f\u8fd8\u5728\u6bd4\u8f83\u9ad8\u7684\u503c\uff0c\u540e\u7eed\u5448\u7ebf\u6027\u589e\u957f\u3002<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u6587\u7ae0\u76ee\u5f55 UDP \u548c TCP \u7684\u7279\u70b9 UDP \u9996\u90e8\u683c\u5f0f TCP \u9996\u90e8\u683c\u5f0f TCP \u7684\u4e09\u6b21\u63e1\u624b TCP \u7684\u56db\u6b21\u6325\u624b TCP \u91cd\u4f20\u673a\u5236 \u8d85\u65f6\u91cd\u4f20 \u5feb\u901f\u91cd\u4f20 SACK\u65b9\u6cd5 Duplicate SACK *\u6817\u5b50\u4e00\u53f7\uff1aACK \u4e22\u5305* *\u6817\u5b50\u4e8c\u53f7\uff1a\u7f51\u7edc [&hellip;]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[44],"topic":[37,40],"class_list":["post-203","post","type-post","status-publish","format-standard","hentry","category-linux","tag-tcp","topic-linux","topic-40"],"_links":{"self":[{"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/posts\/203","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=203"}],"version-history":[{"count":1,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/posts\/203\/revisions"}],"predecessor-version":[{"id":254,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=\/wp\/v2\/posts\/203\/revisions\/254"}],"wp:attachment":[{"href":"https:\/\/idc.birk.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=203"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=203"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/idc.birk.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftopic&post=203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}